With volleys of missiles and laser-guided bombs unleashed against Iraq, the United States and Britain have opened a new chapter in the history of warfare.
In the past, massive military might has been employed to repel invaders, capture and hold territory, or crush insurgencies.
But the attacks on Iraq that began late Wednesday represent the first use of sustained force in a bid to preempt the use of chemical, biological, and nuclear weapons, widely seen as the leading post-cold-war threat to US international interests and global stability.
In unleashing the airstrikes, experts say, the US and Britain show a willingness to resort to military means to curb the threat when diplomatic, political, and economic measures have failed. With that threat expected to grow, the new century could see these partners taking such action again against proliferators.
"We are opening up a whole new uncharted territory," says Joseph Cirincione, a proliferation expert at the Carnegie Endowment for International Peace in Washington. "Once something is used for the first time, it becomes easier to use again. Iraq is a harbinger of future conflicts."
Only once in modern history has a military attack been launched solely to thwart a program of weapons of mass destruction (WMD). That was a limited operation in 1981, in which Israeli war jets destroyed a French-built nuclear-research reactor in Iraq to prevent its use in making an atomic bomb.
As additional evidence of the new US willingness to employ massive and "sustained" force to counter WMD proliferation, experts point to an American initiative, unveiled this month, that would make combating the threat a new mission of the NATO alliance.
The new stance is in line with President Clinton's oft-stated pledge to bolster US military and intelligence capabilities to protect American interests against WMD.
Yet experts, some of whom argue that the spread of WMD is fueled by America's overwhelming superiority in advanced conventional weapons, raise questions about the effectiveness of military force. Short of a full-scale invasion, they ask, can such use of force be any more effective than other measures in stopping determined rulers like Iraqi leader Saddam Hussein from developing WMD?
In the case of biological weapons, they note, a kitchen-size room is big enough to house a production facility and small enough to escape airstrikes. Factories that make baby food or beverages can secretly be adapted to make chemical weapons.
"There is a confluence of factors ... that make it very difficult to fight this fight," says Steve Yetiv, an expert on Iraq at Old Dominion University in Norfolk, Va. "They include the explosion of information, the ability to obtain high-technology materials and tools at low costs, and the ability to develop the intellectual infrastructure."
For this reason, operation Desert Fox is important for countries seeking to halt the spread of WMD - as well as for nations determined to develop them.
The US and Britain launched the operation in response to Saddam's latest effort to conceal the remnants of his pre-Gulf War WMD programs from United Nations weapons inspectors. The attacks - targeting Iraqi military facilities, suspected illicit-weapons facilities, air defenses, and command centers - began with cruise-missile strikes from eight of 22 US warships in the northern Gulf. They were followed by sorties by some of the 210 American and 15 British aircraft based in the region.
After the second wave yesterday, there were no American or British casualties, but US officials said they regretted deaths and injuries among Iraqi civilians.
As the second wave of strikes hit, Mr. Clinton said the attacks had achieved their intended goal. "Our mission is clear: To destroy [Saddam Hussein's] capability to develop and use weapons of mass destruction," he said. "I believe we have achieved that mission."
But his assertion stood in contrast to assessments by other senior US officials, including Defense Secretary William Cohen. They said the attacks would not fully eliminate Iraq's WMD capability, only "degrade" its ability to resurrect them.
For that reason, they make clear that the attacks are only one element of an evolving approach to "contain" Saddam and hamper his ability to destabilize the petroleum-rich Gulf region.
That approach, which Clinton outlined Wednesday, anticipates Iraq's refusal to readmit the UN weapons inspectors and to adhere to UN resolutions mandating its "unconditional" compliance with them.
Instead, the new strategy appears to expand the military's counterproliferation duties beyond this week's airstrikes. The new expectation is that US forces in the Gulf will be required to help ensure that Saddam does not resurrect his WMD programs in the future.
Said Clinton: "We must be prepared to use force again if Saddam takes threatening action such as trying to reconstitute his weapons of mass destruction or other delivery systems."
But many experts question US ability to pursue a counterproliferation strategy that entails an expanded military role. US forces, they note, are already struggling with an unprecedented level of overseas deployments amid manpower cuts.