In The Icarus Syndrome, Peter Beinart analyzes a century's worth of ill-fated American military adventures.

Your crowning example of American hubris is the Iraq War. What fueled that hubris?

The Iraq War was the product of a decade and a half of enormous American military, economic, and ideological success: American military victories, starting with Panama in 1989 and running through the early stages of the Afghan war in 2002; the economic boom; the global wave of democratization and market deregulation of the 1980s and 1990s. The book's theme is that success leads to hubris. People who've seen everything go right lose their sense of fallibility.

You were for the Iraq War before you were against it. Did you share the hubris?

I think so. I wrote the book to try to understand why, on the eve of the Iraq War, I believed things that, in retrospect, were hubristic. The experience of having seen so many countries move from authoritarianism to democracy, often quite rapidly—sometimes, as with Panama, because of [American military] intervention—made me optimistic.

You write that leaders pay a price for telling the American people that there are limits on what foreign policy and the military can accomplish. Can a president pursue a retrenched foreign policy without being voted out of office?

There is an official rhetoric of unbridled optimism that makes talk of limits politically perilous, even anti-American. Any president has to be aware that foreign policy debates are less about what America does overseas than they are symbolic debates about national identity. Ronald Reagan understood that, symbolically, what the nation needed after Vietnam was to feel strong and proud; he was therefore able to pursue what I argue was actually a very cautious foreign policy.

Give President Obama a one-minute prescription for avoiding foreign policy hubris.

Be very careful not to “write checks”—make military and political commitments—that the American people and economy cannot cash. For example, people who suggest military action to prevent Iran from getting a nuclear weapon are not cognizant of the costs of starting a third war in the Middle East. An Iranian nuclear weapon would be a terrible thing, but we should avoid discussing it in apocalyptic terms; when Stalin and Mao got nuclear weapons, it wasn't the end of the world. Also, explain to the American people that military power, if it's not girded by a strong economy, is not a form of strength but of weakness. The central struggles of American foreign policy have been about whether our democratic capitalist model [is] more stable and vibrant than any ideological competitor's. Military efforts that detract from that are counterproductive.