Julian Zelizer is a professor of history and public affairs at Princeton University. He is the author of "Jimmy Carter" and of the new book "Governing America."

(CNN) -- Politics has returned to the water's edge. In the past week, we've seen how international events can suddenly dominate a political campaign, at least for a few days.

The uproar in the Middle East over a YouTube video that featured anti-Islamic messages triggered widespread protests. An attack on the U.S. consulate in Libya left four people dead, including U.S. Ambassador Christopher Stevens. Protests in Egypt were equally intense as some people in a crowd of more than 2,000 scaled the walls of the U.S. Embassy. Protests spread to 20 other countries in the Middle East and beyond. In Tunis, protesters destroyed a school run by Americans while in Afghanistan protesters lit with a torch an effigy of Obama, the U.S. leader once hailed as the president who would repair America's image in the world, and watched it burn up.

Added to this brew was Israeli Prime Minister Benjamin Netanyahu's warning that, in his mind, President Obama has refused to be tough enough with Iran on its nuclear program and the prospect that Israel could take military action against Iran on its own....