One point I've been trying to make in my book talks is that there's precious little evidence that public opinion is demanding a neo-imperial foreign policy for the United States. Nobody felt during the 2000 presidential campaign that the public was clamoring for a new Orwellian doctrine of "anticipatory self-defense" (to repeat the phrase used in Doug Feith's book) in which the United States was going to launch aggressive wars against countries that hadn't attacked us or our allies and had no plans of doing so. September 11, clearly, had a large impact on public opinion but even then there was little public interest in doing this, which is why the Bush administration overstated both the scale and the immediacy of the alleged Iraqi threat while drastically downplaying the costs.
And you see again that while it took a certain amount of courage for Barack Obama to stand up to the crusted-over notion that the United States should set itself up as too damn important to conduct high-level talks with regional adversaries, there's not some genuine avalanche of public opinion on the other side of this issue. What you have instead is a political and media system that's very vulnerable to hype, fearmongering, hysteria, etc. But calm political leadership that doesn't panic at the first sign of conservative self-confidence about the politics of warmongering has a real chance to win these fights.