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.
I want to emphasize that I don't consider intervention in Syria as obviously bad an idea as bombing Iran. Syria is a tragic mess, and, though intervention doesn't seem hugely auspicious, neither do the alternatives. With Iran, in contrast, there are clearly superior alternatives to military action. (One of these is a negotiated deal--a deal that, as I've argued, a first-term Romney administration would have a harder time pursuing than a second-term Obama administration. The other option, in the event that negotiation fails and Iran does choose to develop nuclear weapons, is containment, a policy that both candidates reject, though it seems pretty workable to me.) But, whatever the merits of intervention in Syria, I think it's more likely to happen under Romney than under Obama--not just because a Romney presidency could empower neoconservatives, but also because it could give voice to liberal interventionists.
[Postscript: I've long been meaning to find the time to respond to a response to an earlier post of mine, in which I fretted that the chances of war between Turkey and Syria were at least 50-50 (odds that I'd guess are lower now). Michael Koplow at Ottomans and Zionists did a smart critique of that post, and made some valid points. Still:
 Koplow seemed to not take into account the scenario implied above, in which Romney becomes president, neocons win the struggle for his administration's foreign policy soul, and Turkey, now more confident of American support in the event of war, grows more inclined to escalate fighting with Syria.
 Koplow writes: "In addition, even if Turkey did have the capability to step in and put an end to the sectarian fighting in Syria, Wright assumes that this would put a damper on Kurdish nationalism, but in fact it might very well have precisely the opposite effect. Once the Assad regime falls, the PYD and other Syrian Kurdish groups are likely to try and carve out their own autonomous sphere within Syria, and Turkish intervention on the side of the rebels could accelerate this process." I guess I failed to be clear about what I had in mind. I never said the fall of the Assad regime would "put a damper on Kurdish nationalism," and I actually was imagining that, once Assad fell, a serious bid for Kurdish autonomy or sovereignty would begin. But I was also assuming that the fall of the Assad regime is inevitable, and that the more time Kurds have to prepare for that moment, the more able they'll be to exploit it. So, from Turkey's point of view, the less time the Kurds have to prepare, the better, and therefore the sooner Assad falls the better. Hence the logic of Turkey's angling for a NATO intervention that could hasten the fall, and hence the logic of exacerbating hostilities with Syria. Obviously, that hasn't been happening lately, and, in any event, the fall of the Assad regime may now not be far off. Still, this part of Koplow's critique is in fact consistent with the scenario I had in mind.