Republican U.S. senators warned Iran’s leaders on Monday that any nuclear deal with President Barack Obama could last only as long as he remains in office, an unusual partisan intervention in foreign policy that could undermine delicate international talks with Tehran. The open letter was signed by 47 senators, all but seven of the Republicans in the Senate, and none of Obama’s fellow Democrats, who called it a “stunt.” Iranian Foreign Minister Javad Zarif dismissed it as a “propaganda ploy” from pressure groups he called afraid of diplomatic agreement. In the letter, the senators said Congress plays a role in ratifying international agreements. Noting Obama will leave office in January 2017, they said any deal not approved by Congress would be merely “an executive agreement” that could be revoked by Congress. The White House said the letter was a partisan effort to undermine Obama’s foreign policy […]