WASHINGTON — Janet Napolitano has a message for Canadians: It's a border. Get used to it. The new Homeland Security Secretary had only stern comments yesterday about the state and future of the Canada-U.S. border, at a symposium hosted by the Brookings Institution. Her goal seemed to be to throw a bucket of reality on anyone who hoped that the arrival of Barack Obama's new administration would herald a loosening of new restrictions on cross-border traffic. The days when Canadians and Americans moved back and forth across the border—“it's as though there's not a border at all,” as she put...