Durham, N.C. - When you're a political science professor, you don't expect your research to appear on the front page of The New York Times or spark controversy about the war in Iraq.

But that's what has happened to us recently. Research we conducted with Duke professor Peter Feaver, who is now working with the National Security Council, grabbed the spotlight because of strong evidence suggesting it influenced President Bush's speech at the Naval Academy and accompanying "Strategy for Victory in Iraq."

Indeed, our research supports aspects of what the president has done lately, such as being more candid about the war's challenges and providing clearer benchmarks for success. But the Times article seemed to suggest that it also encouraged the president to try to fool the American people into supporting a war they would otherwise reject.

Not so. Our research actually found that it's not easy to fool the public. When the American people perceive their leaders as distorting reality to advance their own agendas, the leaders generally lose support.

While many factors shape whether Americans will continue to support a military operation with mounting casualties, the data show the most important issue is whether they perceive the mission as likely to succeed.

This conclusion inevitably raises the question of whether their perception is shaped more by reality or spin control. And without a doubt, spin can have an impact. The evidence shows that people are affected by the interpretations of reality they hear from politicians and the media. When asked to define "success" in Iraq, for example, popular responses have reflected the focus of politicians and the media on democracy and Iraqis providing for their own security.

Moreover, as late as October 2004, we found that 32 percent of the pubic believed Iraq possessed weapons of mass destruction prior to the U.S. invasion, despite a lack of any evidence to support this belief. Similarly, 9 percent of respondents, who presumably were listening to other voices, believed "Iraq did not have any activities related to researching or producing weapons of mass destruction" “- a view also not supported by the facts.

Although politicians and the media clearly affect public opinion, the evidence is also clear that reality matters. During the Korean War, for example, public support dropped precipitously as the U.S. suffered a series of battlefield defeats following China's intervention into the war. During the spring and summer of 1951, however, public support rallied “- despite very substantial American casualties - “ as the U.S. pushed Chinese and North Korean forces back up to the 38th parallel.

A mounting body of evidence suggests that public attitudes toward the Iraq War also have responded to facts on the ground. The capture of Saddam Hussein, for example, boosted presidential approval and public perceptions of the likelihood of success in Iraq by nearly 10 percent. The release of the Kay Report and the Abu Ghraib prisoner abuse scandal, on the other hand, each cut presidential approval by about 3 points.

Most importantly, the public's willingness to tolerate the mounting death toll in Iraq has changed in response to real events relating to the success or failure of the U.S. effort. Presidential approval remained strong during the early stages of the war as U.S. forces quickly swept Saddam Hussein from power. But from June 2003 through June 2004, even while controlling for other factors, it declined in response to casualties and the U.S. becoming bogged down fighting an insurgency.

Presidential approval rebounded in June 2004 when the Bush Administration restored sovereignty to Iraq and began preparations for new elections. The president's ability to follow through with his plans, despite many public expressions of doubt, bolstered public optimism about success, or at least progress, in Iraq. Consequently, for the next six or seven months, U.S. casualties had no impact on presidential approval. Only in the spring of 2005, as political deadlock ensued in Iraq and the security situation deteriorated, did the president's approval ratings drop again in response to casualties.

We have no quarrel with the president seeking to communicate his plans and intentions to win the Iraq War, and our research suggests that persuading the public that victory is achievable is indeed likely to stiffen public resolve to continue fighting. But our research does not show that choosing the right words in the absence of action will dupe the public indefinitely into supporting a costly and stalemated war.