WASHINGTON — President Trump welcomed Saudi Arabia’s crown prince, Mohammed bin Salman, to the White House on Tuesday, reaffirming his endorsement of an ambitious young monarch bent on reforming his country and realigning the broader Middle East.

The last time Trump played host to Prince Mohammed at the White House, a year ago, he was jockeying for position in the court of his father, King Salman. This time, with Trump’s enthusiastic support, Prince Mohammed arrives after having rapidly consolidated his position as Saudi Arabia’s heir apparent and a disruptive figure in the region.

The two leaders are expected to take up an array of thorny issues: Trump’s forthcoming decision on whether to rip up the Iran nuclear deal; his nearly completed Middle East peace plan; Saudi Arabia’s bitter dispute with its neighbor, Qatar; and the brutal civil war in Yemen, which has led lawmakers to propose a cutoff in American support for a Saudi-led bombing campaign that has killed thousands.

Prince Mohammed has cut a wide swath in the last year, pushing through radical reforms in Saudi society but also imprisoning more than 380 princes, businessmen, and former government ministers in the Ritz-Carlton Hotel in Riyadh, as part of an anticorruption campaign.