Twice in the past two weeks, the Iraqi opposition has hit high-profile U.S. targets that had been largely beyond its reach, an escalation that might prove more significant strategically than tactically because of the increased political pressure on the Bush administration.
Sunday's handheld missile attack of an Army CH-47 Chinook helicopter was the first lethal downing of a U.S. aircraft in Iraq since major combat operations ended May 1. The attack followed by just a week a sophisticated rocket assault on the Baghdad hotel inside U.S. lines where Deputy Defense Secretary Paul Wolfowitz was staying. That came on top of lethal bombings of the U.N. headquarters in the capital and then that of the Red Cross.
"They are pretty good at surprise and finding the weak spots _ the U.N., then the Red Cross, now this," said Richard Kohn, a military historian at the University of North Carolina at Chapel Hill.
In tactical terms, Sunday's action was troubling but unlikely to result in major changes in how the U.S. military operates on the ground and in the skies over Iraq. Helicopter pilots will be more wary of urban areas, and U.S. commanders probably will order more counter-ambush operations, using aerial surveillance and ground patrols.
But the attack's effects might be more pronounced in the United States.
"It is damaging not only because of the tragic human toll, but also because it looks like a dramatic escalation in lethality and therefore begs obvious questions: Are all helicopters at risk now? Are we losing the initiative? Who is winning?" said Peter Feaver, a former National Security Council staff member who teaches political science at Duke University.
"If the attacks get interpreted as evidence that the Baathist holdouts are winning, then attacks like this can be as lethal for public support as they are for the soldiers involved," he said.
Indeed, the helicopter downing came as two worrisome trends face the Bush administration. In Iraq, there are signs the anti-U.S. opposition is escalating its attacks in numbers and sophistication. Even while the U.S. intelligence haul in Iraq is improving, commanders said the fighters attacking them are becoming more effective.
Meanwhile, the American public's support for President Bush's handling of the war is declining. In a Washington Post-ABC News poll conducted last week, 51 percent said they disapprove of his handling of it.
It was the first time the number of those approving had dropped below 50 percent, and it was more than double the number of those who said they disapproved on May 1. Since then, at least 240 U.S. troops have died in Iraq.
The problem for the Bush administration is the American people have proven tolerant of casualties in military operations they understand and support, but not of those incurred in operations they do not understand or they oppose, according to several studies in recent years by political scientists.
"I think you can see the public is concerned by the continuing slow stream of casualties," said James Burk, a sociology professor at Texas A&M University and one of the academics who has studied public reaction to combat deaths. When there is division about the policy and uncertainty about its costs and duration, he said, relatively small numbers of casualties "can have an important impact."
But Defense Secretary Donald Rumsfeld expressed confidence Sunday that the latest attacks would not undercut public support for the U.S. presence in Iraq.
"I think the American people have a good center of gravity," he said on ABC's This Week. "I think they get it. They see that terrorism is a threat in this world. They would rather have us fighting terrorists outside of the United States of America than inside the United States of America. They know that what's taking place is tragic. . . . But they also know it's necessary."
An additional problem is the American public was not prepared for a long, difficult struggle in Iraq. Even the Pentagon's internal calculation before last spring's war was the U.S. military presence in Iraq could be trimmed fairly swiftly after the fighting, and would be down to about 60,000 by now. More than twice that number of U.S. troops are in the country.
Some predicted the latest fighting, combined with the beginning of the presidential primary season three months from now, will intensify the administration's desire to find a way to get out of Iraq.
"While resolutely denying that it is doing so, the Bush administration is looking for an exit," said Andrew Bacevich, a retired Army colonel who teaches international relations at Boston University. "With the political season approaching, this terrible loss will only increase the urgency felt within the White House to find a way out."
But retired Marine Col. Gary Anderson, a consultant to the Pentagon on Iraqi security issues, said it is clear the only "exit strategy" available is to develop Iraqi security forces to fight the remnants of Saddam Hussein's government. And he predicted that that approach will succeed.
"My cut on this is that time is not on the insurgents' side," Anderson said. "As internal Iraqi security forces come on line, they will be more adept at spotting foreigners and begin to root out Baathist holdouts better than our guys can, with their limited language capability and local cultural knowledge."
ESTIMATED POPULATION: 200,000 to 500,000
LOCATION: On the Euphrates River, 30 miles west of Baghdad. In the "Sunni Triangle," the center of support for Saddam Hussein.
POLITICS: Stronghold of Hussein's Baath Party
VIOLENCE: The area has been a hotbed of resistance to the occupation. Details, see 4A
_ SOURCES: AP, Washington Post, Los Angeles Times, World Gazetteer