Today, the Senate Intelligence Committee will begin questioning Air Force Gen. Michael Hayden, nominated to be director of the Central Intelligence Agency, about the National Security Agency's collection of U.S. citizens' telephone records.

The scrutiny of the NSA is deserved, but the Senate and the American public may be missing a broader and more disturbing development. For the first time since the Civil War, the United States has been designated a military theater of operations. The Department of Defense -- which includes the NSA -- is focusing its vast resources on the homeland. And it is taking an unprecedented role in domestic spying.

It may be legal. But it circumvents three decades of efforts by Congress to restrict government surveillance of Americans under the guise of national security. And it represents a profound shift in the role of the military operating inside the United States. What's at stake here is the erosion of the principle, embedded in the 1878 Posse Comitatus Act, that the U.S. military not be used for domestic law enforcement.

When the administration declared the United States to be a theater of military operations in 2002, it created a U.S. Northern Command, which set up intelligence centers in Colorado and Texas to analyze the domestic threat. But these are not the military's only domestic intelligence efforts. According to the Congressional Research Service, the Pentagon controls "a substantial portion" of U.S. national intelligence assets, the traditional turf of the FBI and CIA.

In 2003, Congress created the job of undersecretary of Defense for intelligence to oversee the department's many intelligence bodies -- including a new entity called Counterintelligence Field Activity, or CIFA.

CIFA was ordered to maintain a "domestic law-enforcement database" on "potential terrorist threats" to U.S. military installations, and it began collecting information on U.S. citizens.

In 2005, a presidential commission suggested that CIFA, set up as a clearinghouse for information, be empowered to conduct domestic investigations into crimes such as treason, espionage and terrorism. Astoundingly, the commission declared that such an expansion of military powers would not require congressional approval; a presidential order and Pentagon directive would suffice. One Defense Department program feeding information to CIFA is TALON (Threat and Local Observation Notice), which is supposed to obtain data from "concerned citizens and military members regarding suspicious incidents" that could herald terrorist attacks. But the military appears to have interpreted its mandate broadly. A TALON report was filed on a protest against "war profiteering" by Halliburton, Newsweek reported. The protesters alleged the defense contractor overcharged for food for U.S. troops in Iraq.

Counterintelligence reports were also filed on New York University's OUTlaw, a decades-old organization of openly gay law students. "The term 'outlaw' is a backhanded way of saying it's all right to commit possible violence," concluded one misguided military investigator in a document obtained last month under the Freedom of Information Act." NBC reported that about four dozen TALON database entries on "suspicious incidents" were not about terrorism but about opposition to the Iraq war and military recruiting.

These misguided military forays into domestic surveillance harken back to Vietnam War-era abuses. This time, they are the result of a much broader intelligence-gathering effort by the military on U.S. soil. President Bush said last week, "We're not mining or trolling through the personal lives of millions of innocent Americans." But a 2004 survey by the General Accounting Office found 199 data-mining operations that collect information ranging from credit-card statements to medical records. The Defense Department had five programs on intelligence and counterterrorism.

The Defense Intelligence Agency, created in 1961 to provide foreign military intelligence, now uses "Verity K2" software to scan U.S. intelligence files and the Internet "to identify foreign terrorists or Americans connected to foreign terrorism activity," and "Inxight Smart Discovery" software to help identify patterns in databases. CIFA has reportedly contracted with Computer Sciences Corp. to buy identity-masking software, which could allow it to create fake websites and monitor legitimate U.S. sites without leaving clues that it had been there. The National Geospatial-Intelligence Agency is collecting data from 133 U.S. cities; intelligence sources told the Los Angeles Times that, when collection is completed, the agency would be able to identify occupants in each house, their nationality and even their political affiliation.

In 2002, the Defense Department launched the granddaddy of all data-mining efforts, Total Information Awareness, to trawl through all government and commercial databases available worldwide. In 2003, concerned about privacy implications, Congress cut its funding. But many of the projects simply transferred to other Defense Department agencies. Two of the most important, the Information Awareness Prototype System and Genoa II, moved to NSA headquarters.

The Pentagon argues that its monitoring of U.S. citizens is legal. "Contrary to popular belief, there is no absolute ban on intelligence" agencies collecting information on Americans or disseminating it, says a memo by Robert Noonan, deputy chief of staff for intelligence. Military intelligence agents can receive any information "from anyone, any time," Noonan wrote.

Throughout U.S. history, we have struggled to balance security concerns with the protection of individual rights, and a thick body of law regulates domestic law enforcement agencies' behavior. Congress should think twice before it lets the behemoth Defense Department into domestic law enforcement.

Iran has climbed to No. 1 on the Washington crisis hit parade. The question of how to stop Iran's nuclear program has unleashed a torrent of punditry. Advocates of diplomacy and a military strike spar on television and in op-ed pages.

Iran's nuclear ambitions deserve our attention. But even by the most alarmist estimates, Iran is years away from being able to build a nuclear warhead.

Meanwhile, over in Northeast Asia, North Korea now has enough fissile material for five to seven weapons and is quietly churning out enough plutonium to build at least one warhead a year, according to rough intelligence estimates. More ominously, work is moving ahead on a new reactor that could potentially produce enough separated plutonium for up to 10 weapons a year.

Somehow this danger prompts no sense of urgency in Washington. After a promising breakthrough last September, the six-party talks to halt the program have lapsed into a stalemate that is close to total collapse.

The Bush administration seems unconcerned. Diplomacy has ground to a halt. The North Koreans refuse to return to the six-party talks. The White House has barred its chief negotiator from talking directly with them, despite Pyongyang's desire to meet and the urging of our six-party partners.

Administration officials have recently floated a report that they are considering a new initiative to negotiate a peace treaty with North Korea. This is a smoke-screen to conceal an empty North Korea policy. According to administration officials, the peace treaty idea has been kicking around for months without going anywhere. South Korean officials tell me that they have been waiting, so far in vain, for any serious detailed discussion of this proposal.

It is the president himself who opposes direct negotiations with Pyongyang, over anything, including a peace treaty. He sees direct talks with North Korea or Iran as an act of weakness. "Somehow,'' he said last month, "the world ends up turning the tables on us.''

In reality, the administration is content to pursue a strategy of going after North Korean counterfeit currency and production of amphetamines and cigarettes, hoping to cut off the flow of funds from these activities. According to administration officials, Under Secretary of State Robert Joseph, the driving force behind this policy, gleefully talks about ``turning out the lights'' in Pyongyang.

Administration officials claim they are drying up slush funds that North Korean dictator Kim Jong Il uses to buy the loyalty of his subordinates. Some even suggest this could trigger a coup against Kim, with the Chinese pulling the strings.

But American intelligence experts who monitor North Korea closely see little evidence to support the conclusion that North Korea is being brought to its knees. Even if the measures are drawing blood, it is self-delusional to believe that this will bring down a regime that has already proven it is willing to starve its own population to stay in power.

The administration seems intent as well on pressing China and South Korea to curb their trade and investment with the North. The administration's special envoy on human rights in North Korea, Jay Lefkowitz, seems to spend most of his time attacking the South for setting up an industrial park in Kaesong in the North. He portrays it as exploiting slave labor. The South Koreans defend it as a vehicle to bring capitalism into the communist North.

The Bush administration's combination of attempted coercion and diplomatic freeze has only two visible effects so far.

First, it lends credence to North Korean claims that the United States, contrary to the joint statement issued last September, is still intent on overthrowing their regime.

Second, it undermines gains made by allowing chief envoy Christopher Hill to hold direct talks with his North Korean counterparts. That demonstrated a flexibility and confidence that disarmed critics, particularly in South Korea, and isolated the North. It strengthened coordination with China and South Korea, the two players with the most leverage over the North.

Now officials in both those capitals again question American readiness to seriously negotiate. Beijing and Seoul are even more convinced that pushing market reforms is the only route to bring the North to give up its nuclear option. Next month former South Korean President Kim Dae Jung will revisit his historic summit with the North Korean leader in 2000.

This growing gap with our allies and partners is deadly. Even if we wanted to opt for coercion, the United States can't do so alone. For that reason, it is urgent that the United States regains the diplomatic upper hand.