Jonathan Bernstein warns 2016 candidates against overindulging in hawkish rhetoric during the campaign:

The problem is that candidates tend to carry out their promises. So the more hawkish the oratory a politician uses on the stump, and the more he or she hires staff who reflect those stances, the more likely military action becomes if that candidate wins the White House. By winning the nomination, a hawkish politician encourages the hawks in the party, and weakens those who are cautious about using force. At the same time, a president who has promised to be tough may (mistakenly) believe that going to war is the path of least resistance. An example of this was Barack Obama on Afghanistan; his surge there was consistent with his campaign rhetoric.

Republican presidential candidates will read the polls and be tempted to up the ante by out-promising one another on Islamic State, Iran, Russia and other foreign hot spots.

As Bernstein explains, committing to hawkish positions as a candidate is potentially perilous because circumstances change (and public opinion with it) and because a candidate who has campaigned on a hawkish platform will then feel compelled to follow through on that campaign rhetoric in the event that he is elected. Even though there appears to be a surge in public support for more aggressive measures in one case (e.g., the war on ISIS), that doesn’t mean that there is broad support for aggressive measures across the board. There may now be more support for sending ground forces against ISIS, but that is almost certainly transitory and support for that option would disappear if it were put into practice. Candidates that take public support for the war on ISIS as a license for pushing hard-line policies on every issue are likely to run into trouble with many primary voters, and if an eventual nominee commits himself to too many hard-line views he is likely to be weighed down by them in the general election.

The danger for the 2016 field is even greater in that essentially the entire likely Republican field has little or no foreign policy experience, which makes reflexive hawkishness even less appealing than it would normally be. It would be one thing if a relatively inexperienced candidate argued for foreign policy restraint and emphasized the limits of American power, but a foreign policy novice pushing for an ambitious and activist role overseas is an extremely hard sell as it should be. Another problem that Bernstein doesn’t mention is that running a thoroughly hawkish campaign will deprive the eventual Republican nominee of the most obvious lines of attack on Clinton’s foreign policy record. Clinton’s record cries out for criticism, especially on the Libyan war, but to make that criticism stick the Republican nominee has to have been an early and consistent critic of foreign interventions. A thoroughgoing hawkish candidate won’t be able to take advantage of any of those weaknesses, and will be exposing himself to attack on a number of fronts.