More broadly, Paul wants to reduce America’s role on the world stage by eliminating foreign aid, closing American military bases in places like Korea, and leaving Israel to its down devices rather than pledging to come to its aid in the case of an attack by Iran or its Arab neighbors.

Taken individually, many of those positions are held by people who wouldn’t otherwise dream of supporting Paul. Sen. John McCain of Arizona, who endorsed Romney, the former Massachusetts governor, has long said that waterboarding should be outlawed. President Obama has vowed to close Guantanamo Bay, though his administration has backed away from that promise in recent months. Liberal lawmakers like Sen. Patrick Leahy of Vermont have deep reservations about the Patriot Act and believe some of its provisions should be eliminated.

Republican stalwarts like former Defense Secretary Donald Rumsfeld, meanwhile, believe U.S. bases in Germany, Japan and Korea have outlived their usefulness and should be shut down or consolidated. With the administration looking for ways of cutting the defense budget, that could easily happen in the years ahead.

Paul’s positions aren’t shared by his primary GOP rivals. And there is little doubt that a President Paul would represent a big departure from the Bush and Obama administrations, at least rhetorically. In practice, however, Congress – particularly if Republicans retake the Senate – would block many of his more controversial positions. Paul would need congressional approval to shutter American bases overseas, pull the U.S. out of the United Nations, or eliminate aid to Israel and other close allies. He likely wouldn’t get it.