Syria hawks have lately been falling back on an argument that echoes the so-called McCain “vengeance doctrine.” This is the idea that the U.S. will reap a bitter harvest of unfortunate consequences if it does not intervene in Syria’s conflict. According to McCain, the danger lies in the resentment that will be felt against America by those on the opposition side. Another variant of this argument that “neglect” of Syria will have longer-term consequences for the U.S. that aren’t immediately apparent. The first version is not very credible, but the second is worth discussing at greater length.

The key flaw with the “vengeance doctrine” is that there are many more likely targets for Syrian oppositionists’ revenge than the country that half-heartedly supported them. It is easy to see how Syrian rebels would take of their anger on Iran, Russia, the Iraqi government, or members of minority communities, but it is extremely rare for members of an insurgency to lash out violently at lukewarm patrons. The “revenge doctrine” just desperate fear-mongering to try to push the U.S. to increase its role in the conflict, and the desperation shows.

A more sophisticated version of the “non-interventionist blowback” argument is that the U.S. sometimes ends up paying a price for refusing to interfere. Shadi Hamid stated this view earlier this week:

It is a very curious definition of a “non-interventionist” policy that includes these as examples. The major failing of the Bush administration wasn’t its refusal to back the Shia uprisings in 1991, but its irresponsible call for Iraqis to overthrow their government when there was no intention of backing them militarily. Not content with expelling Iraqi forces from Kuwait, Bush evidently felt the need to make a gesture of opposition to Hussein’s continued rule, but he wasn’t willing to commit to more than that. The lesson to take away from that episode is that presidents shouldn’t say things that create the false expectation of U.S. support. Supposing that the U.S. had done what Hamid recommends, it still would have put the U.S. in the position of toppling Hussein and occupying Iraq. There would have been a protracted U.S. military presence in Iraq, but it would have started at an earlier date. Bush and his advisers understood that the costs of doing this were unacceptably high, which was something that members of his son’s administration failed to understand.

The other examples are even less persuasive. The U.S. and France supported the Algerian government and military. They may have been wrong to do so, but that isn’t an example of a non-interventionist policy having undesirable consequences. The civil war in 1990s Afghanistan was at least partly a product of the arming of anti-Soviet insurgents by the U.S. and its clients. As it did with many of its proxy forces at the end of the Cold War, the U.S. stopped paying much attention to the messes it helped create by arming insurgents, but Afghanistan wasn’t riven by conflict in the 1990s because the U.S. hadn’t involved itself in the country. The country suffered from prolonged conflict in part because the U.S. had been funneling arms to insurgents, which is the very thing that Syria hawks now call on the U.S. to do today.

Strictly speaking, none of these episodes resulted in blowback for the U.S.