In reality, a more libertarian, less interventionist foreign policy may be in the cards whether Governor Christie likes it or not. Multiple constraints are driving America towards less intervention:
First, our military infrastructure is shrinking, rapidly. With the drawdown from Afghanistan, the end of the Iraq war, the sequester, and continued budgetary pressures, we may well see an Army of less than 400,000 active-duty troops. Large-scale interventions require large-scale forces, and the smaller size of all the major branches of the military will create its own limitations.
Second, there is little military or civilian appetite for nation-building. Nothing short of a direct attack on our country or a close ally (like South Korea) would currently motivate Americans to put substantial numbers of troops on the ground in harm’s way. There’s a reason why millions of Americans grew tired of our engagement in Afghanistan (and, before that, Iraq) that had nothing to do with pacifism or even ideology: quite simply, while they wanted to defeat our enemies, they were weary of attempting to transform near-medieval cultures. By late 2006 the Surge may have presented the best chance to defeat al-Qaeda in Iraq, but let’s not forget that the Surge was made necessary by many of our own military and diplomatic mistakes.