No U.S. President has done more to confront Iran ‘s nuclear program than Donald Trump, and one reason is to avert a nuclear arms race in the world’s most volatile region. Vice President JD Vance made that case recently, yet the Trump Administration is simultaneously advancing a civil nuclear deal with Saudi Arabia that would abandon long-held proliferation safeguards. Why?

A State Department letter to Sen. Ed Markey (D., Mass.) dated May 18 says the Saudi deal is undergoing “final review” before Mr. Trump can submit it to Congress, Reuters reports. The deal wouldn’t require Riyadh to sign the Additional Protocol for snap U.N. inspections or adhere to the “gold standard” of no domestic uranium enrichment and no reprocessing of nuclear waste. That has been the U.S. standard to ward off nuclear-weapons proliferation.

Saudi Arabia is a U.S. ally, but so is the neighboring United Arab Emirates, which committed to the gold standard in its 2009 civil nuclear deal with the U.S. There’s no legitimate reason for Riyadh to dodge those restrictions or the most effective method of inspections.

The State Department letter says the U.S. and Saudi Arabia instead would have to come to a “bilateral safeguards agreement.” Reuters reports that it would be less onerous than the tried-and-tested gold standard and Additional Protocol, and a central question is whether it will prohibit enrichment and reprocessing.

Each time these processes–keys to the world’s most dangerous weapons–are let out of the bag, the risk of something catastrophic increases. Mr. Trump understands this in the case of Iran’s regime, a rogue and an enemy, but decades of U.S. strategic thinking has recognized that it holds true for allies as well.

Regimes can change, and so can alliances. Technology and materials can be transferred or stolen. And once a country begins to enrich uranium, it is difficult to stop it. Even after U.S. and Israeli strikes in June halted Iran’s enrichment, the regime threatened to resume before long with a few essential materials and facilities and its accumulated know-how.

Saudi Arabia’s Mohammed bin Salman has mused before about needing nuclear weapons. As we wrote during the Crown Prince’s November trip to Washington, “The better way to reassure the Saudis–and everyone else–is to keep Iran’s nuclear program in ruins.” No one can accuse Mr. Trump of inactivity there, which should decrease the risk of regional proliferation.

This deal would do the opposite by weakening safeguards and overturning a valuable precedent. If it advances, expect other allies to request the same treatment and the world to become that much more dangerous.

– The Wall Street Journal