U.S.-Saudi Relations Buckle, Driven by Animosity Between Biden and Mohammed bin Salman

RIYADH, Saudi Arabia—An unwritten pact binding the U.S. and Saudi Arabia has survived 15 presidents and seven kings through an Arab oil embargo, two Persian Gulf wars and the Sept. 11 terrorist attacks. Now, it is fracturing under two leaders who don’t like or trust each other.

Saudi Crown Prince Mohammed bin Salman, the kingdom’s 37-year-old day-to-day ruler, mocks President Biden in private, making fun of the 79-year-old’s gaffes and questioning his mental acuity, according to people inside the Saudi government. He has told advisers he hasn’t been impressed with Mr. Biden since his days as vice president, and much preferred former President Donald Trump, the people said.