The debate over U.S. foreign policy is often inflicted with false claims of "isolationism," but in this instance Paul correctly called out Rubio as "acting like an isolationist who wants to retreat to our borders and perhaps build a moat."

Rucker notes that "the emerging, younger libertarian wing [of the GOP] represented by Paul" may want a different foreign policy from that established by George W. Bush. Neoconservatives and allies of other Republican presidential candidates insist that Republicans have no intention of rethinking the policy of promiscuous interventionism.

Bill Kristol of the Weekly Standard tells Rucker that Sen. Rand Paul is "a lonely gadfly" on foreign policy:

"Rand Paul speaks for a genuine sentiment that's always been in the Republican Party, but maybe it's 10 percent? 15 percent? 20 percent? I don't think he's going to be a serious competitor for guiding Republican foreign policy."