President Biden ended an arduous four-day visit to the Middle East over the weekend without a major success to appease his liberal base, which has criticized him for pandering to oil-rich autocrats and walking back a campaign pledge to make a pariah of Saudi Crown Prince Mohammed bin Salman. After a closed-door meeting with Saudi leaders Friday, Mr. Biden appeared to acknowledge his failure to achieve a major goal of the trip: to persuade Saudi Arabia to increase its oil production for the global market. Although he made no firm commitments to abandon the stalled nuclear talks with Iran, the president vowed during a stop in Israel and during his visit to Saudi Arabia that the U.S. would not allow Iran to obtain nuclear weapons.