U.S. Defense Secretary Ashton Carter will soon head to Saudi Arabia to discuss ways to increase cooperation in the war against the Islamic State. But there’s little indication he will be able to restore a vital relationship that’s become riven with distrust in the last year, which would require him to reassure the Saudis on the very nature of the U.S. commitment to the kingdom and the region.

Carter is slated to meet on April 20 in Riyadh with Mohammed Bin Salman al Saud, the 30-year-old deputy crown prince and defense minister who is widely believed to be in contention to succeed his father, King Salman. Carter’s visit will come one day ahead of President Barack Obama’s stop there for a leaders’ summit between the U.S. and the countries of the Gulf Cooperation Council, a follow-on to their meeting at Camp David last May. FULL REPORT