News reports suggest that the Trump administration is poised to “decertify” the Iran nuclear deal. (Atta Kenare/AFP/Getty Images)

This article was first published on Sept. 25. It has been updated to reflect President Trump’s announcement that he plans to decertify the Iran nuclear agreement. 

The Trump administration faces an Oct. 15 deadline to certify to Congress that Iran is complying with the terms of the 2015 Joint Comprehensive Plan of Action (JCPOA), commonly known as the Iran nuclear deal, and that the agreement is in the national interests of the United States.

News reports suggest that, after months of publicly criticizing the deal, the Trump administration is poised to “decertify” the agreement. While the International Atomic Energy Agency has repeatedly confirmed that Iran is in compliance, as have senior members of the Trump administration, the White House has argued that Iran is violating the “spirit” of the deal and that agreement is not in U.S. interests.

What happens next will send a far broader signal about the U.S. commitment to nonproliferation 

While a decision to “decertify” the deal would not immediately blow up the JCPOA, it could lay the groundwork for Congress to reimpose sanctions on Iran. This, in turn, might lead Iran to exit the agreement and ramp up its nuclear program to pre-2015 levels, raising the risk of proliferation or preventive war.

Trump may be using decertification as leverage to renegotiate the deal but faces a rocky road, given Iranian opposition and the reluctance of many of the other “P5+1” partners involved in brokering the deal: China, France, Russia, the United Kingdom and Germany.

Trump’s decision is important not only because of its implications for Iran and the wider Middle East. The decision is also crucial because of what it will communicate about the broader U.S. commitment to nonproliferation.

U.S. nonproliferation efforts have achieved notable success

For decades, preventing the spread of nuclear weapons has been a top U.S. priority. As I argue in a forthcoming book, U.S. policies help explain why there are only nine countries with nuclear weapons today — in contrast to the much higher numbers forecast in the early years of the nuclear age.

Historically, Washington’s effort to limit the spread of nuclear weapons has rested on four key pillars — but each is showing signs of crumbling:

1. Credibly opposing proliferation

In the late 1960s, the United States worked with the Soviet Union to conclude the Non-Proliferation Treaty, which laid the foundation of the nonproliferation regime. Starting in the 1970s, the United States has threatened and imposed sanctions against friends and foes alike that have sought nuclear weapons.

There are mixed signals coming out of Washington today. During the 2016 campaign, Trump stated that it would be okay if Japan, South Korea or Saudi Arabia acquired nuclear weapons. In March, Secretary of State Rex Tillerson refused to rule out Japanese or South Korean proliferation.

2. Reassuring allies

A second essential element of U.S. nonproliferation policy is the extension of security guarantees and the U.S. nuclear umbrella to allied states. U.S. protection not only reduces the odds that allies feel the need to develop nuclear weapons, it also provides leverage if an ally does begin seeking nuclear weapons.

Trump’s “America First” foreign policy has raised significant doubts about U.S. alliance commitments, including to NATO, South Korea and Japan. U.S. allies were already skittish for reasons unrelated to Trump — namely, Russia’s renewed belligerence and North Korea’s rapid nuclear advances. Today, South Koreans, Japanese, and even Germans have renewed debates about hosting nuclear weapons or developing their own nuclear arsenals.

3. Reducing the salience of nuclear weapons

Over the past few decades, the United States has drastically reduced the size of its nuclear arsenal. President Barack Obama declared a goal of moving to a world without nuclear weapons (but his administration also supported an expensive program to modernize the U.S. nuclear arsenal).

The tone has markedly changed under the Trump administration. Shortly before taking office, Trump welcomed an arms race and called for the United States to “greatly strengthen and expand its nuclear capability.” In recent months, Trump has lobbed a number of grisly nuclear threats, warning of “fire and fury” and promising to “totally destroy North Korea” in the event of a North Korean attack.

And the Trump administration reportedly is considering developing new “mini-nukes,” with the aim of making nuclear weapons more usable in a conflict.

4. Providing a diplomatic exit to proliferators

U.S. nonproliferation policy also has succeeded when it offered adversaries a diplomatic off-ramp — by abandoning nuclear weapons programs, they can gain improved relations with the United States. In 2003, for example, the George W. Bush administration agreed to lift sanctions on Libya and drop a policy of regime change in exchange for Libya giving up its weapons of mass destruction programs. A similar principle informed the JCPOA, as the P5+1 lifted sanctions in exchange for limits on Tehran’s nuclear program.

This type of bargain is viable only when Washington can credibly assure its adversaries that it will uphold negotiated arrangements. The credibility of U.S. assurances was already highly questionable before Trump made the matter worse by threatening to scuttle the JCPOA. Over the past 15 years, the United States has launched an invasion of Iraq ostensibly for nonproliferation reasons — even though it had already disarmed — and supported the overthrow of Moammar Gaddafi even after he agreed to give up Libya’s weapons programs.

Here’s what this means for the Iran deal and U.S. nonproliferation policy

If the JCPOA ultimately breaks down because of U.S. actions, it might permanently cement the perception that there is no durable diplomatic off-ramp for adversary proliferators.

Think of it this way: If the United States cannot be trusted to abide by a bargain and will sanction or invade your country even if you agree to limit your nuclear program, why would you agree to any limits? A viable nuclear deterrent is the one thing that might prevent a U.S. invasion, after all. This logic explains why many analysts warn that withdrawing from the JCPOA would cripple any hopes of achieving limits on the North Korean nuclear program diplomatically.

Undermining the JCPOA would also strengthen the perception that Washington is not truly committed to opposing proliferation. A weakened or collapsed JCPOA would increase the incentives for countries such as Saudi Arabia to seek their own nuclear weapons. And it would signal that the United States prioritizes preventing missile tests, hemming in Iranian support for proxy groups, and achieving regime change in Iran over nonproliferation.

Given that several core pillars of U.S. nonproliferation policy are already showing signs of stress, the fate of the JCPOA may be even more important than it initially seems.

Nicholas Miller is an assistant professor of government at Dartmouth College. His book, Stopping the Bomb: The Sources and Effectiveness of U.S. Nonproliferation Policy,” is forthcoming from Cornell University Press in 2018. Find him on Twitter, @Nick_L_Miller.