I believe that a full investigation would lead the U.S. public to, ultimately, side with torture, side with the torturers, and side against the prosecutors. That's why we can't proceed and Obama probably understands that. If another attack happened this would be all the more true.I don't share Cowen's pessimism about Americans, but I see his point: The coalition to make the United States do a full accounting for torture and indefinite detention since 9/11 doesn't yet have enough numbers to override the apparent desires of President Obama and the Congressional leadership to move on, to say nothing of the Republican Party's eagerness to declare waterboarding as American as apple pie. At the same time, that isn't to say that the coalition that does exist couldn't go after some low-hanging fruit; e.g., the impeachment of Jay Bybee or the firing of John Yoo.
On top of everything else, major Democrats in Congress are likely complicit and the Democrats as a whole hardly made this a campaign issue in 2004; in 2008 the economy was their winning issue, not torture.
The American public, now having affiliated itself with torture, will be reluctant to condemn torture for some time to come. The "endowment effect" here seems to be strong.
An acquittal or mistrial would lose the chunk of world opinion that Obama has been winning back. And a trial might prompt another terrorist attack, if only to force acquittal and make America look bad once again.
Pushing for prosecution would more likely endanger rule of law than preserve it, which is a sorry state of affairs.
But, while nailing Bybee, Yoo, et al (I assume an investigation of Bush and Cheney is highly unlikely) would be desirable, I ultimately think preventing torture from happening again is more important than pursuing investigations, especially if the latter come to nothing.* And that means discrediting the use of torture as an instrument of national security: The disturbing thing about the torture debate is how many people (and not only conservatives) seem willing to set aside morality in the hopes that torturing prisoners will keep them safe, given that torture has historically been used to extract false confessions, as Matt Yglesias and others have said ad nauseam. How you prove to the larger public not only the immorality of torture, but its uselessness, is a question I can't answer now. Certainly an improved security situation under the Obama administration would go a long way toward demonstrating that a humane foreign policy is a strong foreign policy. But I welcome reaction on this from those who know more about national security policy than I do.
* Of course, prohibiting torture and investigating the perpetrators of torture aren't mutually exclusive. But the danger of a full-scale investigation, as in Cowen's example, is that we as a country will not thus come to the consensus that torture is wrong and we shouldn't do it anymore. That consensus can possibly be achieved with the help of prosecutions, but prosecutions, by themselves, are not sufficient to achieve it.