Two Democratic senators threw crucial support behind the Iran nuclear deal on Tuesday, almost assuring that President Obama would have the votes to overcome congressional opponents seeking to derail the landmark accord. The announcements by the senators, Bob Casey of Pennsylvania and Chris Coons of Delaware, came a week before the Senate returned to formally debate a Republican resolution disapproving the accord among Iran and six world powers. With the support of Mr. Casey and Mr. Coons, the chances of Congress torpedoing it are becoming ever more slim. Mr. Coons, an outspoken voice on the Senate Foreign Relations Committee, received personal, written assurances from Mr. Obama on Tuesday on a […]