Netanyahu has long trumpeted his ties to Trump. But the president is sidelining him on urgent issues like the Iran nuclear talks and the conflict with Houthi rebels.

As President Donald Trump sets out for the Middle East in the first international trip of his second administration, signs of disagreements have emerged between the U.S. leader and one of the men who most enthusiastically welcomed his return to office.

Both men are politically divisive, fiercely combative and have outsize egos. But as Mr. Trump arrives in the Middle East next week, the fate of the region could hinge on their relationship.