Despite recently expressing doubts about America's relationship with Saudi Arabia, U.S. President Barack Obama again flew to Riyadh and sought to "reassure" the Saudi royals about U.S. support.

In fact, the Kingdom of Saudi Arabia raises the question: what are allies for? If the president wants to leave his mark on American foreign policy, he should have started moving Washington and Riyadh toward a more normal relationship.

Most important, the United States should drop any security guarantee, whether explicit or implicit. If Saudi Arabia is worth defending, its own people should do so. At the same time, the U.S. should take a more even-handed approach in the Iranian-Saudi cold war, looking for opportunities to draw Tehran away from Islamic extremism.