President Obama begins a delicate mission Wednesday both to reinforce his strategic aims in the Middle East and to ease tension with an aggrieved longtime ally, Saudi Arabia.
Neither will be easy.
After he lands in Riyadh, the Saudi capital, he will meet privately with King Salman, who has clashed with White House efforts on Iran, the wars in Yemen and Syria, and the battle against Islamic State.
The White House characterized the visit as a follow-up to talks in May when Obama hosted the leaders of America's Persian Gulf allies at the presidential retreat at Camp David. Salman stayed home in what diplomats called a snub.
Little came of the summit beyond a flurry of...