I recently argued that America is more likely to wind up in a war with Iran if Mitt Romney is elected president than if President Obama is re-elected. The idea wasn't that Romney is any more eager to attack Iran than Obama. Rather, Romney is less likely to reach a negotiated solution to the Iranian nuclear issue--and the longer that issue goes unresolved, the more likely war is to happen, whether via American attack, Israeli attack, assassination tit-for-tats that get out of hand, a misconstrued naval mishap in the Persian Gulf, whatever.
But Iran isn't the only place where a Romney presidency would increase the chances of American involvement in war. The second most likely venue is Syria. I'm not saying Romney is likely to get American militarily involved in Syria--just that he's more likely to do so than Obama is.
The two most plausible paths to involvement are (1) a Turkish-Syrian conflict that draws NATO into full-fledged war on behalf of NATO member Turkey; or (2) a decision by the US and/or NATO to intervene in a limited way, such as establishing a no-fly zone and/or establishing a buffer zone on the Syrian side of the Syrian-Turkish border for the settlement of refugees.
These things become more likely with a Romney presidency for two reasons, one of which is widely appreciated and one of which isn't.
The widely appreciated reason is that, if Romney's foreign policy team winds up looking anything like his current team of foreign policy advisers, it will include a fair number of neoconservatives. And what American enthusiasm there is for intervention in Syria resides largely in neocon circles. "Intervention," actually, could wind up being an understatement. Some neoconservatives see Syria as a gateway to Iran, which means their version of intervention could wind up broadening the war rather than hastening its end.
The second, largely unappreciated reason a Romney presidency would raise the chances of intervention has to do with the one other place in America where there's support for a Syrian intervention: among liberal interventionists. Some of these liberals have been biting their tongues on this issue because they're Obama supporters and don't want to be seen criticizing Obama, especially right before an election. But if Romney wins the election, you can expect them to pipe up. (I stole this insight from Robert Farley, who uttered it on the BhTV show Foreign Entanglements, which he co-hosts with Matthew Duss.)
In other words: Come late January, we could have a neocon/liberal-interventionist coalition supporting intervention, with neocons well-represented in the White House. Sound familiar?
Possibly mitigating circumstances:
 There's a chance the neocons would lose the struggle for a Romney presidency's soul and some of Romney's more moderate advisers, such as Bob Zoellick, would dominate foreign policy. (Though even Zoellick signed one of the early Project for a New American Century letters that were part of the neocon campaign that culminated in the invasion of Iraq.) In that case chances of involvement in Syria would decline.
 The Assad regime could well fall by late January. Even so, given the significant chance that Assad's fall would be followed by continued fighting along sectarian lines, the situation could long remain sufficiently chaotic for arguments in favor of intervention to persist.