Despite fond White House hopes that the nuclear deal would moderate Iran’s behavior, Tehran hard-liners wasted no time this week disqualifying thousands of moderate candidates from running in next month’s parliamentary elections, and an Iranian-backed militia appears to be responsible for the recent kidnapping of three Americans in Iraq.

No wonder the Saudis are nervous. The nuclear deal guarantees Iran a $100 billion sanctions windfall that will offset its losses from falling oil prices while doing nothing to stop its regional imperialism. Russia’s military support for the Assad regime in Syria, along with its sale of advanced weaponry to Tehran, means that Riyadh’s regional enemies now enjoy the protection of a major nuclear power. Armed Iranian proxies are active in Lebanon, Syria and Yemen, and dominate much of southern Iraq. Restive Shiite populations in Saudi Arabia’s oil-rich Eastern Province and neighboring Bahrain provide further openings for Iranian subversion on the Arabian peninsula.

Add to this an American president who is ambivalent about the House of Saud the way Jimmy Carter was about the Shah of Iran, and no wonder Riyadh is acting the way it is. If the administration is now unhappy about the Saudi war in Yemen or its execution of Shiite radicals, it has only itself to blame.

All this means that the right U.S. policy toward the Saudis is to hold them close and demonstrate serious support, lest they be tempted to continue freelancing their foreign policy in ways we might not like. It won’t happen in this administration, but a serious commitment to overthrow the Assad regime would be the place to start.