Secretary of State John Kerry, left, shakes hands with Iranian Foreign Minister Mohammad Javad Zarif last year at the Radisson Blu Hotel in Oslo. (State Department/European Pressphoto Agency)

I vigorously opposed the Joint Comprehensive Plan of Action (JCPOA) because I believed then — as I believe now — that the Obama administration, in its desperation for a legacy-creating deal, negotiated a weaker deal than we could have obtained. The JCPOA did not deliver anywhere/anytime inspections as promised or constrain Iran’s ballistic missile program. The JCPOA provided sanctions relief up-front and contains a highly troubling sunset clause. Nevertheless, the agreement is in place now, and the question is whether to stay in or exit. Circumstances have undeniably changed, both because of the new president and the operation of the deal itself. Here I part company with many who opposed the deal and now want the United States to exit.

Both supporters and opponents of the original deal rightly point out the unworkability of a U.S. withdrawal.

Max Boot, who opposed the deal, writes:

I would not recommend pulling out of the deal now — not when the International Atomic Energy Agency, whose inspectors monitor 27 separate sites, has certified that Iran is in compliance. Instead of nuking the nuclear deal, the United States should take other steps to check the growth of Iranian influence.

It would send a terrible signal to other states that in the future might be interested in concluding an arms control treaty with the United States if Washington were to abrogate a treaty simply because of a change of administrations. Why would anyone trust Washington to keep its word ever again?

Pulling out of the treaty now would isolate not Iran but the United States. If the Trump administration simply leaves the treaty, without re-imposing meaningful sanctions on Iran, the effect would be purely symbolic — and the symbolism would be of America standing alone. . . .Pulling out of the Iran deal without a reasonable provocation would only create international sympathy for Iran in spite of its appalling human-rights violations — and it would most likely leave the agreement in place anyway.

He doubts we’d be able to coax Iran back to the table. He asks “why would Iran, which resisted any [further] limits in 2015 at a time when it was under heavy sanctions, agree to them now, after already having gotten an economic windfall from having sanctions lifted? Even if [President] Trump can now re-impose some penalties, it will not be nearly as many as existed prior to the Iran deal.”

Brian Katulis of the Center for American Progress supported the JCPOA, so its critics might discount his argument for remaining in the deal. However, the rationale for not exiting is strikingly similar to Boot’s in some respects:

Without European support—and the reimposition of European sanctions in particular—it is unlikely the United States will be able to strike a better bargain on Iran’s nuclear program. Moreover, if the United States attempts to unilaterally reimpose secondary sanctions on foreign companies doing business with Iran, countries such as China and India will likely ignore or circumvent such measures. . . .

There is little reason to believe that Trump’s combination of bluster, strategic impatience, international isolation, and diminished leverage would produce a better deal. In fact, there are many reasons to worry that the outcome will be a broken agreement, unnecessarily heightening the risk of military conflict or nuclear breakout

Like Boot, Katulis et al. worry: “Whatever slim prospects exist today for a diplomatic resolution of the North Korea question will evaporate should President Trump provide concrete proof that the United States cannot be trusted to honor its agreements.”

So what can be done? Boot argues there are a range of options if we want to “curb Iran’s dangerous designs without scrapping the agreement, negotiating a new treaty with the mullahs, or going to war against them”:

The Trump administration is already … imposing sanctions on companies linked to Iran’s ballistic missile program, its cyberattacks, and its terrorist-sponsoring Islamic Revolutionary Guard Corps (IRGC). There is much more to be done on the targeted sanctions front, including designating the IRGC a terrorist organization. But there are also important steps that Trump can take on the ground in Syria and Iraq. …

In the case of Iraq, that would mean insisting that, once the Islamic State is defeated, the government disband the Popular Mobilization Forces, made up mostly of Iranian-backed militias, and create a Sunni civil guard to protect Sunni areas from Shiite aggression. That will not be easy to do, but the United States can gain important leverage if it does not bring its troops home after the Islamic State is defeated — if, that is, it does not repeat the mistake that former President Barack Obama made in 2011.

(Incidentally, had the Trump administration really wanted to reverse Obama policy and deny a foothold to Iran in Syria, it would not have ceded the country to Vladimir Putin and his junior Tehran partners via an ill-conceived cease-fire.)

Katulis et al. likewise see avenues to pressure Iran and contain its nuclear and non-nuclear ambitions. In addition to expanding our intelligence capacity and our intelligence-sharing with regional allies, they recommend stepped-up interdiction of material and weapons “to terrorist and militant groups undermining regional stability: Hezbollah in Lebanon, Hamas in the Palestinian territories, Houthis in Yemen, and Shia militias in Iraq.” They also favor “clear redlines when it comes to interference with freedom of navigation and U.S. naval operations and be prepared to back them up with action. Overall, the goal should be to deter Iranian proxies from taking actions that either inherently destabilize the region or have the potential to ignite a larger conflict.”

On the topic of Iran’s ballistic missile program, Katulis et al. argue that the “United States should continue the substantial investments it has made to enhance regional partners’ missile defense capabilities. It should also step up the efforts of diplomatic, intelligence, and law enforcement entities to prevent sales and shipments of technologies that have helped Iran increase its ballistic missile capabilities.”

We agree it would be a mistake to construct a flimsy case accusing Iran of violating the JCPOA. Even more damaging would be a unilateral pullout without the support of our allies. Trump would wind up cementing his reputation as an irresponsible aggressor. A combination of sanctions in response to non-nuclear activities (e.g. human rights violations, regional aggression, missile testing) and improvement of our military posture and intelligence capabilities in the region would be the best short-term solution.

Moreover, let’s not forget that it’s the regime, not the Iranian people, with whom we have serious differences. Katulis et al. write on this topic: “The United States also needs to compete in a battle of ideas to inspire the people of the region, address longstanding drivers of instability, and offer a better alternative to Iran’s ideological agenda. … A more credible, consistent approach would raise the pressure on Iran at home; help deny it opportunities abroad; and position the United States to address drivers of instability in the years ahead.” Such actions would not commit us to military-backed regime change any more than such efforts committed us to military overthrow of the Soviet Union during the Cold War.

Short-term containment with the long-term objective of a peaceful and non-jihadist Iran is the best — I would argue, the only — viable Iran approach at this point. Frankly, thinking Trump can handle simultaneous nuclear confrontations with North Korea and Iran is a dangerous delusion.