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.

Three months ago the Russian energy giant Gazprom forced Ukraine to pay sharply higher prices for natural gas. At the time, the story was portrayed as a political struggle for control in Kiev. But last week Gazprom announced it was tripling gas prices in Belarus, a country that is politically close to the Kremlin. Moldova has been forced to accept a doubling of prices over the next three to four years, and the other former Soviet republics are already paying market prices for Russian gas.

The truth is that these price increases are not political. Rather, they reflect worrisome economic and geological facts about Russian gas fields. The Kremlin is not simply trying to use Gazprom to reassert authority in Belarus, Ukraine or anywhere else. There are in fact deep problems with Gazprom -- problems created by its inefficient management and a looming decline in gas production.

Russia controls over a quarter of the world's gas reserves -- more than any other country. Most of the known Russian reserves (about 80 percent) are in west Siberia and concentrated in a handful of giant and super-giant gas fields. Since the early 1970s the rate of discovery for these new fields has been declining. Moreover, output from the country's mainstay super-giant fields is also steadily falling.

Huge investments are needed to replace this dwindling supply, and all the options for new production will prove costly and difficult. New fields in the far north and east of the country are distant from most of Russia's people and export markets, requiring wholly new transport systems such as pipelines. Moreover, most of these fields are found in extremely harsh environments where it is technically and financially difficult to operate.

Gazprom controls neither the capital nor the technology that will be needed. The state-controlled company is already deeply in debt and burdened by many expensive obligations, such as supplying Russia's population and friends with cheap gas. The company has to work with foreign partners.

So far Gazprom has been able to forestall crisis. Economic stagnation across the former Soviet Union and Eastern Europe since 1990 dampened gas demand. Russia, which had a surplus at the time, sharply increased its gas exports and made contractual commitments that will remain in force for many years.

But following the long stagnation, Russia's internal gas consumption is rising again as the economy expands. And new Russian policies to promote development of the country's eastern regions will, in the next few years, require large new commitments to supply gas to that region (along with spending on railroads, airports and other infrastructure).

Even when the Russian economy was in the doldrums the country was notable as a large gas consumer because of its extremely inefficient energy system. Today Russia is the world's second-largest gas user, after the United States, although its economy is only one-twentieth the size of the U.S. economy.

Electricity in Russia is produced for the most part by gas, but the country's gas-fired electric generators work at 33 percent efficiency on average, compared with 50 to 55 percent in Europe. More than 90 percent of residential and industrial gas consumers don't have meters. Gas is even cheaper than coal -- Russia is the only large country where that is true -- so incentives to switch to an abundant fuel are weak.

In recent years Russia has boosted gas supplies by squeezing Turkmenistan to sell gas to Russia at a deep discount. But Turkmen gas production is poised to decline, and Turkmenistan's gas industry is barely functional because the country's political environment is scary for long-term investors. Other Central Asian suppliers, notably Kazakhstan, are unlikely to be able to bridge the gap.

Caught between growing internal consumption of gas, continued inefficiency and mounting external obligations, Russia's gas industry faces a looming crisis. Given the country's vast resources, it seems that many producers could fill the void. But a series of policy decisions created two roadblocks that Gazprom has been happy to reinforce. One is the lack of access to the Gazprom-controlled pipeline network, which explains why few companies even bother to look for gas: They know they can't get what they find to market. The other barrier to investment is the low internal prices, which make gas production uneconomic except for companies that can sell their products outside.

Gazprom needs cash -- much more cash -- for investment. At the same time, it needs a strong incentive for former Soviet republics to cut their own very inefficient consumption.

Analysts have ignored the risk that Russia's supplies could fall short because they focus on Russia's vast gas resources and the new Western investors who are -- albeit cautiously -- entering into joint ventures with Gazprom. But those resources and ventures are for the long term, and the looming crisis of supply is unfolding now.

The gas shortage is likely to become most acute over the next few years. If there is an unusually cold winter in 2008, the year of Russia's presidential election, then Gazprom will face a politically unpleasant choice: whether to cut off internal customers (voters) or the Western customers who are the firm's main source of hard cash.

The writer is a research fellow at the Program on Energy and Sustainable Development at Stanford University. She is co-author of "Axis of Oil" and of a forthcoming comprehensive review of Russia's gas pipelines.

The fierce debate on immigration ignores a crucial reality -- what is happening to the United States is only one piece, although a big one, of a much larger global picture.

That hit me a couple of weeks ago when I was in Singapore. The Southeast Asian island nation has long been hailed as an economic model, the business capital for the entire region.

But it is an economy facing demographic peril. Its small population of 4 million is shrinking, thanks to a very low fertility rate. Prosperous Singaporean couples work hard, have fewer children and worry about how to take care of their aging parents. By 2050, Singapore will have a median age of over 52, one of the oldest in the world.

Singapore's answer is to import labor. A third of its workforce are migrants, from construction workers to maids. One out of seven households employs a domestic worker -- low-paid women mostly from neighboring Philippines and Indonesia.

Singapore tries to lure "talents'' -- highly skilled and affluent migrants -- to stay permanently. But the men hauling bricks and the maids washing laundry are in a separate class of temporary guest workers, with no chance to join Singaporean society. If a maid becomes pregnant, she is shipped out within seven days. Employers have to post bonds that must be paid should their servants break the rules and try to stay, putting them in the role of migrant police.

Problems of abuse of domestic workers, including physical and sexual violence and confinement, are serious enough to have prompted a report last December by Human Rights Watch.

Singapore's dependence on migrant labor and its guest-worker policy may be at the extreme end but it's very much on the global spectrum. Labor, like capital and goods before it, is part of a global market. The movement of people across borders in search of wages and work, most of it from developing countries to developed, is growing at a phenomenal pace.

The numbers are staggering. From 1980 to 2000, the number of migrants living in the developed world more than doubled from 48 million to 110 million. Migrants make up an average 12 percent of the workforce in high-income countries. About 4 million migrants cross borders illegally every year.

The demand for labor is driven in part by a demographic disaster -- the falling birth rates of developed countries. Almost all of those countries now have fertility rates that are well below 2.1, the level at which a population replaces itself. At the very low end are Hong Kong (0.94), Korea (1.22) and Singapore in Asia (1.24), along with much of Eastern Europe.

Low fertility means shrinking workforces and aging populations. Without migration, according to a recent study, Europe's population would have declined by 4.4 million from 1995 to 2000. Immigration accounted for 75 percent of U.S. population growth during the same period.

This movement of people cannot be stopped, certainly not by hundreds of miles of fences or even by tens of thousands of border guards. It is an issue that cries out for global cooperation, for common policies that cut across national boundaries. Already, we can benefit from looking at what has worked -- and not worked -- elsewhere.

A Global Commission on International Migration, formed in 2003 by the United Nations secretary-general, has taken an initial stab. Their report, issued last winter, supports the growth of guest-worker programs.

The Senate immigration bill now up for debate includes a provision for a guest-worker program. The bill is clearly preferable to the punitive and ineffective approach of the House version. But the Singapore experience -- and previous guest-worker programs like the German import of Turks -- should prompt second thoughts about going down this road.

One problem is that the guests don't leave. The United States has its own experience with this in the bracero program to import farmworkers, and more recently with the supposedly temporary H1-B visas used so extensively by the high-tech industry here in Silicon Valley.

Most troubling to me, these programs create an underclass of migrants who are never assimilated, as happened in Germany. It sets us on the Singapore road, encouraging inhumane policing mechanisms. And it is a gilded invitation to employers to depress the wages and incomes of American workers, and not just in the dirty jobs that are supposedly so hard to fill.

The United States has been rightfully proud of a tradition that treats all immigrants as citizens in the making. Rather than guest workers, isn't it more American to set realistic immigration quotas and enforce them fairly?

The Honorable Joschka Fischer, member of the Bundestag, and former German Foreign Minister and Deputy Chancellor (1998-2005) in the government of Gerhard Schroeder, will offer a 2006 Frank E. and Arthur W. Payne policy lecture titled "Europe's Prospects in a Globalized World," on April 20, 2006, 4:30 p.m., Bechtel Conference Center, Encina Hall.

The Honorable Joschka Fischer's Biography: