Does the conflict in Iraq amount to a civil war? In many ways, the public debate over this question is largely political. Calling Iraq a "civil war" implies yet another failure for the Bush administration and adds force to the question of whether U.S. troops still have a constructive role to play.

Politics aside, however, the definition of civil war is not arbitrary. For some -- and perhaps especially Americans -- the term brings to mind all-out historical conflicts along the lines of the U.S. or Spanish civil wars. According to this notion, there will not be civil war in Iraq until we see mass mobilization of sectarian communities behind more or less conventional armies.

But a more standard definition is common today:

1) Civil war refers to a violent conflict between organized groups within a country that are fighting over control of the government, one side's separatist goals, or some divisive government policy.

By this measure, the war in Iraq has been a civil war not simply since the escalation of internecine killings following the bombing of a Shiite shrine in Samarra in February, but at least since the United States handed over formal control to an interim Iraqi government in June 2004.

Here's why: Although the insurgents target the U.S. military, they are also fighting the Shiite-dominated Iraqi government and killing large numbers of Iraqis. There is little reason to believe that if the United States were suddenly to withdraw its forces, they would not continue their battle to control or shape the government.

Political scientists who study civil war have proposed various refinements to this rough definition to deal with borderline cases. One issue concerns how much killing has to occur -- and at what rate.

2) For a conflict to qualify as a civil war, most academics use the threshold of 1,000 dead, which leads to the inclusion of a good number of low-intensity rural insurgencies.

Current estimates suggest that more than 25,000 Iraqis have been killed in fighting since the U.S.-led invasion in March 2003 -- a level and rate of killing that is comparable to numerous other conflicts that are commonly described as civil wars, such as those in Lebanon (1975-1990) and Sri Lanka (beginning in 1983).

The organization -- or rather, disorganization -- of the warring communities in Iraq means that a large-scale conventional conflict along the lines of the U.S. Civil War is unlikely to develop. More probable is a gradual escalation of the current "dirty war" between neighborhood militias that have loose ties to national political factions and are fighting almost as much within sectarian lines as across them.

This is roughly what happened in Lebanon and at a lower level in Turkish cities in the late 1970s. Ethnic cleansing will occur not as a systematic, centrally directed campaign (as in Bosnia), but as a result of people moving to escape danger.

And there's another twist to the terminology:

3) If the conflict in Iraq becomes purely a matter of violence between Sunni and Shiite communities driven by revenge and hatred rather than by political goals, many political scientists would say that it is something other than civil war.

Almost no one, for example, calls the Hindu-Muslim violence in India a civil war.

A civil war has to involve attempts to grab power at the center of government or in a given region, or to use violence to change some major government policy.

In Iraq's case, however, the vacuum of power at the center means that communal violence will inevitably be tied to struggles for political power and control.

A final complication concerns the nature of international involvement. Some argue, for example, that the war in Bosnia should be seen as an interstate war rather than a civil war, since the Bosnian Serb forces were armed and directed largely by Belgrade. Post-Mobutu violence in Congo is often termed a civil war, even though fighters have been closely tied to armies from neighboring states.

4) A conflict may be both a civil and an interstate war at the same time.

The Vietnam War, for instance, clearly comprised both a civil war in the South and an interstate war involving the North, the South and the United States.

Iraq may be moving in this direction. The United States and Britain are already openly involved, and such neighboring countries as Iran and Syria are more covertly involved. Not that it matters to the people dying there, but the next debate here may turn on whether what is already a civil war in Iraq should be viewed as an interstate war as well.

A recent report from Duke University that critiques the supposed gap between the number of American science and engineering (S&E) graduates and those of merging economies -- especially China's -- has led to false reassurance that the U.S. lead in science and technology is not under threat from China. It would be a grave mistake to drop our concerns about China's competitive challenge.

First, the Duke report simply claimed that China's true number of science and engineering bachelor degrees was 351,000, rather than the widely reported 600,000. Coupling this with an upward adjustment for American graduates still left China producing 214,000 more such degrees than the United States.

Moreover, undergraduates are only part of the concern. China's production of those with doctorates has increased rapidly. By 2003, China's homegrown science and engineering doctorates numbered almost half of the U.S. total.

Chinese were also earning large numbers of doctorates abroad. In 2001, the number of Chinese S&E doctorates earned in Japan, the United Kingdom and the United States equaled 72 percent of the total of S&E doctorates earned by American citizens and permanent residents.

Since 1975, China has increased its global share of S&E doctorates from zero (courtesy of the Cultural Revolution) to 11 percent, not counting doctorates earned overseas. During the same three decades, the U.S. global share has fallen from half to roughly 22 percent.

More worrisome than the aggregate numbers is American universities' reliance on foreigners who earn doctorates. In engineering, foreigners account for over half of America's doctorates, and in computer science just under half.

If foreign-born holders of doctorates continued to stay in the United States, we wouldn't have to worry. Unfortunately, there are many signs that it is becoming much harder to retain them.

One need only look at the flow from Taiwan, one of the former main sources of American S&E doctoral degrees, to see what could happen. Up until 1994, Taiwanese earned more science and engineering doctorates in the United States than members of any other foreign nationality. By 2000, their numbers had plummeted because economic and educational opportunities at home were more appealing.

The Taiwanese didn't just stop coming to America. They also began to leave. As Taiwan's tech sector boomed in the 1990s, huge numbers of Taiwanese technologists (estimates range as high as 100,000) left America for home and took their technical skills with them.

Our two current biggest foreign sources of technologists, China and India, appear to be following Taiwan's path. China has begun to lure back large numbers of technologists. China's central and local governments offer free office space and other benefits to attract technologists home. These inducements are working. A 2005 survey of the Chinese American Semiconductor Professionals Association's members showed that the vast majority regard China as the most likely future work destination, and they rated Shanghai higher than even Silicon Valley on career potential. India's recruitment efforts have also started to bear fruit.

The challenge is not simply keeping up the numbers of technologists in America. China by many measures has improved its technological capabilities. On the Georgia Institute of Technology's Index of Technological Capability, China has more than doubled its index score over the past decade. China now ranks fourth behind the United States, Japan and Germany.

This rapid ascent is not surprising given China's increasing investments. China's research and development spending as a percentage of gross domestic product has tripled to 1.3 percent in the last decade, even while its GDP has ballooned. Few emerging economies spend even 1 percent of their GDP on research.

U.S. patents invented in China are also on the rise. Information-technology patents from corporations' Chinese technologists have risen from 134 in 1997-2001 to 482 during 2002-04. As a first step to meet this challenge, we should increase federal spending on basic and exploratory research. Our R&D spending has been flat at 2.6 percent of GDP for four decades, but the share of federal spending has declined from two-thirds to one-quarter.

Given that corporations now de-emphasize basic scientific research, the federal government should further support the basic research that could maintain our lead at the cutting edge of technology.

Increased federal funding would also address the issue of the falling share of investment in certain disciplines. With spending flat, the rising share commanded by biomedicine has meant a falling share spent on engineering and physics.

Federal support may also play a direct role in increasing interest in pursuing a science education. Since the 1950s, the number of undergraduate S&E majors in America has risen and fallen in line with federal research funding, as Professor Henry Rowen of Stanford University has pointed out.

Before meeting China's challenge, we first must recognize it. Complacency in reaction to "good'' news that China is producing fewer S&E graduates than commonly thought is not the answer.

Analysis of the Indian-U.S. nuclear agreement, as well as substituting natural gas for coal in fueling the Chinese electricity sector, reveals that side agreements between developed and developing countries could result in massive greenhouse gas emission reductions.

Before attacking Iraq in March 2003, the United States told the world that Saddam Hussein had reconstituted his nuclear weapons program in defiance of the United Nations. That claim, used to justify the war, was based on assessments provided by the United States intelligence community. But as everyone now knows, those assessments were wrong. So Jeffrey T. Richelson's history of American nuclear intelligence, including our attempts to learn about Iraq's nuclear program, could hardly be more timely.

In "Spying on the Bomb," Richelson, the author of several books on American intelligence, has brought together a huge amount of information about Washington's efforts to track the nuclear weapons projects of other countries. He examines the nuclear projects of Nazi Germany, the Soviet Union, China, France, Israel, India, South Africa, Taiwan, Libya, Pakistan, Iran and North Korea, as well as Iraq. Through interviews and declassified documents as well as secondary works, he sets out briefly what we currently know about those projects and compares that with assessments of the time.

This may sound like heavy going, but Richelson writes with admirable clarity. And along the way he has fascinating stories to tell: about plans to assassinate the German physicist Werner Heisenberg during World War II; about discussions in the Kennedy and Johnson administrations on the possibility of attacking Chinese nuclear installations; about Indian measures to evade the gaze of American reconnaissance satellites; and about the bureaucratic infighting over the estimates on Iraq.

The United States has put an enormous effort into gathering information about the nuclear projects of other countries. After World War II it equipped aircraft with special filters to pick up radioactive debris from nuclear tests for isotopic analysis. It created a network of stations around the world to register the seismic effects of nuclear explosions. Most important, in 1960 it began to launch reconnaissance satellites that could take detailed photographs of nuclear sites in the Soviet Union and China. Richelson occasionally speculates about the role of communications intercepts and of spies, but these appear from his account to have been much less important than the other methods of collecting information.

Through these means the United States has gathered a vast quantity of data, sometimes to surprising effect. Intelligence played a crucial role in the cold war, for instance, by reducing uncertainty about Soviet nuclear forces. Alongside such successes, however, there have been failures. One notable example concerned the first Soviet test, which took place in August 1949, much sooner than the C.I.A. had predicted. Another was the failure to detect Indian preparations for tests in May 1998, even though at an earlier time the United States, with the help of satellite intelligence, had managed to learn about preparations the Indians were making and to head off their tests.

But the most serious failure of all was in Iraq in 2003, because in no other case did the intelligence assessments serve as justification for the use of military force. The information needed for avoiding political surprise is one thing. That needed for preventive war is quite another, if only because of the consequences of making a mistake.

Beyond making the uncontroversial recommendation that "aggressive and inventive intelligence collection and analysis" should continue, Richelson draws no general conclusions. That is a pity, because his rich material points to issues that cry out for further analysis. He suggests in one or two cases that failures sprang from the mind-set of the intelligence community, but he does not elaborate on this point. He has little to say about relations between policy makers and the intelligence community, even though the quality of intelligence and the use made of it depend heavily on that relationship.

His focus is no less narrow in his discussion of foreign nuclear projects. He concentrates on the programs themselves, paying very little attention to their political context. Does that reflect a technological bias in nuclear intelligence? Would, for example, the prewar assessment of Iraqi nuclear capabilities have been more accurate if it had paid more attention to the broader political and economic circumstances of Hussein's regime?

The task of intelligence has become more complex than it was during the cold war. A single dominant nuclear opponent has now been replaced by a number of nuclear states, along with states and stateless terrorists that are aiming to get their hands on nuclear weapons. Meanwhile, the technology needed for producing nuclear weapons has become easier to acquire.

Many critics believe the recent performance of the intelligence community shows it has not responded adequately to this new situation. Richelson does not have much to say on this question; nor does he discuss the likely impact of the current reforms, initiated in response to the Iraq war, on the quality of intelligence. His reticence may imply that he does not think reform is necessary. Still, it is disappointing that he does not draw on his historical survey to discuss whether new approaches are needed for dealing with nuclear threats, and, if so, what those new approaches might be.

Stanford, California - If the deal to supply India with nuclear technologies goes through, future generations may remember it for quite different reasons than the debate over nuclear proliferation.

Nuclear power emits no carbon dioxide, the leading cause of global warming. And India, like most developing countries, has not been anxious to spend money to control its emissions of this and other so- called greenhouse gases.

India is embracing nuclear power for other reasons - because it can help the country solve its chronic failure to supply the electricity needed for a burgeoning economy. But in effect, the deal would marry their interest in power with ours in protecting the planet.

India is growing rapidly. In recent years its economy has swelled at more than 7 percent per year, and many analysts believe it is poised to grow even faster in the coming decade.

The economic growth is feeding a voracious appetite for electricity that India's bankrupt utilities are unable to satisfy. Blackouts are commonplace. Farmers, who account for about two-fifths of all the power consumed, can barely rely on getting power for half of every day. In industrial zones, the lifeblood of India's vibrant economy, unstable power supplies are such trouble that the biggest companies usually build their own power plants.

So most analysts expect that the demand for electricity will rise at about 10 percent a year. (For comparison, U.S. power demand notches up at just 2 percent annually.)

Over the past decade, about one third of India's new power supplies came from natural gas and hydro electricity. Both those sources have been good news for global warming - natural gas is the least carbon- intensive of all the fossil fuels, and most of India's hydroelectric dams probably emit almost no greenhouse gases.

However, the bloom is coming off those greenhouse-friendly roses. New supplies of natural gas cost about twice what Indians are used to paying, and environmental objections are likely to scupper the government's grand plans for new hydro dams.

That leaves coal - the most carbon-intensive of all fossil fuels. Already more than half of India's new power supplies come from coal, and that could grow rapidly.

Traditionally, the coal sector was plagued by inefficiencies. State coal mines were notoriously dangerous and inefficient. Coal-fired plants in western provinces, far from the coal fields and vulnerable to the dysfunctional rail network, often came within days of shutting operations due to lack of coal.

All that is changing. Private and highly efficient coal mines are grabbing growing shares of the coal market. Upgrades to the nation's high-tension power grid is making it feasible to generate electricity with new plants installed right at the coal mines.

These improvements make coal the fuel to beat.

So the deal struck with President George W. Bush matters. At the moment, India has just 3 gigawatts of nuclear plants connected to the grid. Government planners envision that nuclear supply will grow to 30 GW over the next generation, but that will remain a fantasy without access to advanced nuclear technologies and, especially, nuclear fuels - such as those offered under the deal with the Bush administration.

By 2020, even after discounting for the government's normal exuberance in its forecasts, a fresh start for nuclear power could increase nuclear generating capacity nearly ten-fold.

By displacing coal, that would avoid about 130 million tons of carbon dioxide per year (for comparison, the full range of emission cuts planned by the European Union under the Kyoto Protocol will total just 200 million tons per year).

The effort, if successful, would eclipse the scheme under the Kyoto Protocol, known as the Clean Development Mechanism, that was designed to reward developing countries that implement projects to reduce their emissions of greenhouse gases. The largest 100 of these CDM projects, in total, won't reduce emissions as much as a successful effort to help India embrace safe nuclear power.

The benefits in slowing global warming are not enough to make the deal a winner. Care is needed to tame the risks of proliferation, especially those connected from India's system of breeder reactors that make more weapons-capable fuel than they consume. And complementary efforts, led by Indians, are needed to fix the trouble in India's electricity sector that have so far discouraged private investors.

None of this will be easy. There are no silver bullets in cooling the greenhouse.

What is important is that the deal is not just a one-off venture, as the administration's backers, on the defensive, have suggested. It could frame a new approach to technology sharing and managing a more proliferation proof fuel cycle that, in turn, will multiply the benefits of a cooler climate.

Coal-rich China is among the many other countries that would welcome more nuclear power and whose emissions of carbon dioxide are growing fast - even faster than India's.

Quite accidentally, it seems, the Bush administration has stumbled on part of an effective strategy to slow global warming. Now it should marry that clever scheme overseas with an effective plan here at home.

The nuclear deal reached during President Bush's recent visit to India unleashed a predictable wave of criticism. From editorial and op-ed pages to Congress, led by the left but supported on the right, the administration has been assailed for making a bad bargain.

Under the agreement, which still needs congressional approval, India would open much of its nuclear facilities to international inspections in return for gaining access to the world's supplies of uranium and U.S. nuclear expertise.

The attacks on the deal reflect the view of the nonproliferation lobby -- the experts and policymakers whose central concern is to stop the spread of nuclear weapons. I share their aim. But American arguments against the India deal are misleading and only expose the deep contradictions, if not hypocrisy, of our own nuclear policies.

There are two main criticisms of the agreement: first, it undermines the Nuclear Nonproliferation Treaty, the NPT, and second, it permits, even encourages, India to expand its nuclear weapons production.

The NPT issue is particularly sensitive at a time when the international community is trying to persuade Iran to give up certain nuclear technologies which many nations fear are part of a secret bomb program.

The NPT created two sets of global rules -- one for the five nuclear weapons powers it recognizes (China, the United States, Russia, Britain and France) and another for everyone else. The five, for example, allow only "voluntary'' international safeguards on their civilian nuclear facilities. They have no obligation to open their military programs to any kind of scrutiny. And the NPT places no real limits on their arsenals, other than a vague commitment to reduce and eventually eliminate all nuclear weapons.

The rest must open their nuclear energy programs fully to international inspection and agree never to build bombs. In exchange, they gain access to the peaceful uses of nuclear energy.

Iran -- and North Korea -- made that bargain and can be held to account for breaking the rules. But India consistently regarded that as an unequal trade-off and never signed the NPT; neither did Pakistan and Israel, two other nuclear weapons states.

India's nuclear program is the product of decades of largely indigenous effort; it did not result from secretive proliferation in violation of the NPT.

The deal with India turns the five into six. It treats India as a de facto member of the inner club. The deal would require changes in U.S. law to remove existing restrictions on the transfer of nuclear energy technology, changes that would allow India to be treated no differently from China.

That does not weaken the NPT -- it strengthens it. It brings it more into accord with reality and gives India a stake in a system it had previously rejected as unfair. It paves the way for India to join the Nuclear Suppliers Group, the international organization that controls nuclear exports.

The critics are right that the deal enables India to expand its production of fissile materials to make nuclear warheads. Eight of India's 22 power reactors will remain outside international controls, along with a new breeder reactor. The Indians fought for that exemption because they feel their nuclear arsenal may not be large enough to deter a nuclear first strike by Pakistan or China in the future. Critics fear that with increased access to uranium and limited inspections, India will set off an arms race in South Asia.

Again, the agreement simply treats India like the five. Nonproliferation experts claim that unlike India, however, the five have halted their production of plutonium and highly enriched uranium that could be used to build new weapons. This is true, but misleading.

The five have massive stockpiles of fissile material built up during the Cold War. "If I've got a full pantry, it's easy for me to swear off trips to the supermarket,'' said Michael Levi, an arms-control expert at the Council on Foreign Relations.

Moreover, the United States has embarked on a new program to rebuild its nuclear weapons production capability, including creating new facilities to produce plutonium cores for warheads and to assemble them.

India has agreed to back a global pact to cut off fissile-material production. But the Bush administration does not support a treaty that would actually verify this is taking place. And the U.S. Senate has refused to ratify the Comprehensive Test Ban Treaty that would permanently halt any new testing of nuclear weapons.

A Congress that can support those policies is hardly in a position to challenge the administration's agreement with India. Rather than block the U.S.-India deal, it makes more sense to improve it. This could include reaching agreements for cooperation between the two countries to ensure the safety and security of nuclear facilities, including those for military purposes, suggested Stanford Professor Scott D. Sagan, a leading expert on nuclear safety and nonproliferation. "Reducing the risk of terrorist theft of nuclear materials or weapons in India would also help protect the United States,'' argues Sagan.

Beyond that, the six acknowledged nuclear powers should begin to seriously fulfill their part of the NPT bargain -- to cap fissile-material production, to ban nuclear testing, and to eventually radically reduce stored arsenals of nuclear weapons and materials.