India, May 25 -- President Donald Trump is standing behind the peace agreement his administration is working out with Iran, even as some of his own party members say the deal looks too weak. Trump posted on Saturday night that a deal had been "largely negotiated" following talks with Gulf leaders and other US allies in the region. On Sunday, he said negotiations were "proceeding in an orderly and constructive manner" and that "time is on our side." He also said the relationship with Iran was becoming "a much more professional and productive one."

The backlash came quickly from hardline Republicans who felt the deal did not go far enough, particularly because it does not immediately settle the question of Iran's nuclear program, which was...