Michael Barone makes  a very odd claim about Republicans’ post-Iraq foreign policy views:
Most Republican politicians seem disinclined to suggest we should intervene anywhere else.
If Barone means that most national Republicans aren’t going out of their way to demand new wars, then I suppose he has a point, but when the subject comes up I don’t see a lot of evidence that most of them are “disinclined” to support more military interventions. There are more Congressional Republican skeptics of military intervention and interference in foreign conflicts than there used to be, and that is not simply because the other party controls the White House. However, it isn’t true that they make up a majority of the members or anything close to it right now. That could change over time as more new members are elected to the House and the Senate, but so far most of the members of the classes of 2010 and 2012 are moving in the opposite direction. One might think that new members that have no connection to the Iraq war would be more than ready to distance themselves from everything that it represents, but what we have seen instead is a competition between most of the new members to prove just how aggressive and hawkish they can be. It was much the same story during the 2012 primaries  and in Romney’s general election campaign.
We shouldn’t expect that many Republican politicians to go out of their way to defend and celebrate the Iraq war, so I don’t consider the “silence” of most Republicans in office to be very important. Even if they agree with most other Republicans  nationwide that the war wasn’t a mistake, they’re not likely to re-fight debates specifically over Iraq when most Americans take the opposite view. There are still some limits to the party’s apparent need to self-destruct. Judging from the response of most conservative media outlets to the war’s anniversary, I don’t see any signs that war supporters on the right have learned anything from the Iraq experience other than discovering new ways to make even more  torturous justifications  for the unnecessary war  they supported until the end.
Barone speculates at the end:
If he [Obama] follows up on his threat to attack Iran’s nuclear program, we could have a 2016 presidential race in which Republican Rand Paul criticizes military action and Democrat Hillary Clinton defends it.
Of course, attacking Iran would be an act of supreme folly, and it would harm whichever party was most closely associated with it. Once Americans started realizing the war’s costs  to the global economy, the U.S., and regional stability, the political backlash at home would be severe. Many Democrats would likely rally to support the decision to start a war with Iran out of partisan loyalty, if for no other reason, but launching a war with Iran would very likely fracture the coalition Obama has assembled and produce a split among national Democratic leaders. The Democrats might nominate an Iran hawk, but that is by no means guaranteed. Assuming that Clinton ran and supported the decision to attack, she would be putting herself on the wrong side of yet another major foreign policy decision and probably a majority of her own party as well, which might conceivably be enough to deprive her of the nomination for a second time. Rank-and-file Republicans remain generally much more hawkish  on Iran, so it seems reasonable to assume that the Republicans would nominate an Iran hawk and then criticize the management of the war. Despite the political advantage opposition would give the GOP, an Iran war could perversely make it less likely that someone like Paul could win the nomination.