Daniel Larison thinks Robert Kagan is wrong to suggest that Senator Rand Paul is not a "true" foreign policy dissenter because then he "would have the temerity to declare that a nuclear Iran, although unfortunate, is nevertheless tolerable and that the military option ought not to be on the table." According to Larison, that's not the way politics works:
Kagan knows very well why Sen. Paul doesn’t take a more unconventional line on Iran policy. We have seen it on display for the last seven weeks in the panic over Hagel’s nomination and we have seen it over the last six years as Sen. Paul’s father has been written off as a “fringe” figure because he takes exactly the position on Iran that Kagan describes. Obviously, Kagan isn’t interested in having a “true dissenter” in the debate, and he hates them when they appear.
While I think Larison is right about the practical results, I wonder if Kagan doesn't have a point. It all goes back to the Overton window. For the uninitiated, here's the theory:
The Overton window is a means of visualizing which ideas define that range of acceptance by where they fall in it. Proponents of policies outside the window seek to persuade or educate the public so that the window either “moves” or expands to encompass them. Opponents of current policies, or similar ones currently within the window, likewise seek to convince people that these should be considered unacceptable.
Kagan and his fellow advocates both within government and in think tanks and journalistic institutions have had a fair degree of success in moving this window in their direction. Whenever a civil war breaks out in countries within or adjacent to regional interests of the United States, there is an implicit expectation that Washington "do something." By defining America's sphere of interest so broadly (Kagan, remember, believes the U.S. should exercise hegemony over the very Earth itself) they have succeeded in moving the policy debate onto grounds that are already favorable, even if they don't get every war or intervention they desire.
The problem is that the Overton window does not move back in a direction of less intervention through nuanced critiques of the most extreme position. Believe me, I wish it did. Instead, it needs to move using the same kind of stridency and demagoguery that pushed it in its original direction. So while I personally wouldn't agree with categorically ruling out the use of force against Iran no matter what, opponents of preventative war are going to have to make some politically risky declarations if they expect the consensus to start to move in their direction.