Saudi Crown Prince Mohammed bin Salman, the kingdom’s de facto leader, spoke by phone with President Donald J. Trump early last week to convey the concerns of Saudi Arabia, the United Arab Emirates, Qatar, Oman, and other Arab allies, who warned that strikes against Iran could destabilize regional security and harm the economy, with potential repercussions for the United States, according to a Saudi diplomat and a U.S. official cited by The Washington Post.