“From the end of the Bush years up through 2013 and ’14, there was a war weariness that was permeating even Republicans,” said David Boaz, author of a new book “The Libertarian Mind.” “However, the videos of ISIS beheading Americans and other people have certainly made it more difficult to stick to a noninterventionist argument.”

After doing penance after the debacle in Iraq, it suddenly seems acceptable for the GOP to be hawkish again. Republicans like Jeb Bush and Ted Cruz have lacerated the Obama administration’s national security policy and managed to get to Paul’s right on national security.

“The anti-interventionist wave I do think has crested and those issues are moving away from Rand Paul now,” said Fergus Cullen, the former chairman of the New Hampshire Republican Party.