Within days of the terrorist attacks on Sept. 11, pollsters began asking Americans questions about their patience with the U.S. response and their willingness to accept casualties.

Eighty-six percent told Gallup-CNN-USA Today interviewers on Sept. 13-14 that they would support military action that would continue for a “period of several months.” Two-thirds said they would support action that would continue “for a period of years.” Sixty-seven percent in late September told ABC News-Washington Post interviewers they would support taking action if it meant “getting into a long war” with large numbers of casualties. According to Zogby International’s daily tracking, roughly two-thirds would be very supportive and a quarter would be somewhat supportive of a war that “lasts six months to two years.” Approximately 55 percent said they would be very supportive, and around a quarter somewhat supportive, of a war that “lasts two to five years.” A third question found that about 40 percent are very supportive and 25 percent are somewhat supportive of a war that “lasts five years into the next generation.”

Sixty-five percent in the Gallup-CNN-USA Today poll said they would support military action if 1,000 American troops would be killed, and 84 percent would approve of it even if it resulted in the deaths of 5,000 more U.S. civilians. In late September, 68 percent told CBS News-New York Times interviewers that we should take military action even if it means “many thousands of innocent civilians may be killed.”

It’s natural to want to know how patient Americans will be about the war effort. But the polls can’t tell us because they are not real tests. Still, survey data provide important clues about how Americans have responded in past conflicts.

In a commentary written before the Gulf War started, the late Everett Carll Ladd argued against the prevailing notion that the public first responds emotionally by rallying around the flag, but that “As soon as a substantial price must be paid--the conflict is not quickly resolved or many American lives are lost--support wanes.” More than 50 years of research, he said, finds that when the public is “satisfied the objectives are sound and compelling, [it] backs military action. It may withdraw this support at some future point, but then because it has decided the goals are not being effectively advanced, not because . . . its patience has run out.”

John Mueller, now at Ohio State University, argues that both the Korean and Vietnam wars began “with about the same amount of support.” Support for both, he says, declined as a logarithmic function of American casualties. “While support for the war in Vietnam did finally drop below the levels found during Korea, it did so only after the war had gone on considerably longer and only after American casualties had far surpassed those of the earlier war.” As late as February 1968, 61 percent of Americans told Gallup interviewers that they were hawks, and just 23 percent claimed to be doves. In March 1969, almost four years after the country had sent a half-million troops to battle, just 19 percent said they favored ending the conflict “as soon as possible,” 26 percent wanted the South Vietnamese to take over, 19 percent wanted current policy to be continued, and a third were in favor of the United States going all out for a military victory.

More recently, Steve Kull and Clay Ramsay, writing in Public Opinion and the International Use of Force, examined U.S. attitudes toward military fatalities in the past 15 years--in Somalia, in the Gulf War, at Kobar Towers, and perceived casualties in Bosnia. They argue, “Polls show little evidence that the majority of Americans are prone to respond to fatalities by wanting to withdraw U.S. troops. If anything the public is more likely to want to respond assertively.” Kull and Ramsay contend that it is not body counts or an assessment of whether a situation represents a vital interest, but rather whether the public thinks a mission can succeed (see www.pipa.org).

Also reviewing polls over the past 15 years, Gary Langer of ABC News suggests, “Public support for military action by the United States is not automatic.” However, he notes that when it’s given, “it tends to last.” Elements that build support, Langer adds, such as a sense of threat to the nation, a belief that vital interests are at stake, and a clear policy with a specific purpose, are clearly present today.

Karlyn H. Bowman is a resident fellow at AEI.