Mujtaba Rahman is the head of Eurasia Group’s Europe practice. He posts at @Mij_Europe . The war in Iran has improved U.K. Prime Minister Keir Starmer’s chances of remaining in office. Make no mistake, his underlying position is still weak. Yet as the tenuous ceasefire looks like it may unravel, the likelihood of Starmer facing a leadership challenge after the May 7 regional elections to the Scottish and Welsh parliaments and English councils is falling. In fact, Labour members of parliament