The bigger domestic change may have come in terms of the public’s attitude towards war. In the fifteen years after the end of the Cold War, the U.S. public became more tolerant towards the use of force than it had been in the post-Vietnam era. The Iraq War changed that, dramatically; today, few serious candidates for President support even a limited land war against ISIS. 

President Obama won the 2008 Democratic primary because of his opposition to the Iraq War in 2003, and whatever one’s attitude towards the drone war, the Obama administration clearly favors a less interventionist policy than its predecessors. This preference seems to accord with public and elite opinion about the use of force.

Does this reticence limit U.S. strategic options?  America assisted France, the United Kingdom, and Libyan rebel forces with the deposition of the Gaddafi regime in 2011, notwithstanding any reluctance to use force.  The U.S. continues to carry out a drone-and-special-forces war against Al Qaeda, across the Middle East. However, the reluctance to use force has surely played some role in the Obama administration’s reaction to the Syria conflict, which has raged with minimal American intervention for the last four years.