Politico’s Andrew Desiderio highlights a statement from Senator Bob Menendez (D‑NJ), who has long been one of the most hawkish Democrats on Iran and opposed the JCPOA when it was signed:

Iran now has enough enriched uranium to produce a nuclear weapon. This latest milestone returns us to a familiar question: At what point will the Administration acknowledge that Iran’s nuclear advances make a return to the 2015 JCPOA not in the United States’ strategic interest?… it is time for a comprehensive strategy to address Iran and the threats it poses—Iran as it is, not the Iran we might hope for.

Let’s look at Iran’s nuclear advances and see if we can figure out what’s going on.

Below are three charts showing Iran’s nuclear advances since 2018. The first looks at enriched uranium—defining low-enriched uranium as under 5% enrichment, then one showing enrichment up to 20%, then the last one showing the (much riskier) 60% enriched uranium. This is IAEA Board Report data, with my (appalling) visualization:

Chart showing Iran's nuclear enrichment

Next we can look at Iran’s installed advanced centrifuges since 2017:

Iran's Installed Advanced Centrifuges

Finally, here is one highlighting in particular the advances in Iran’s holdings of medium-enriched uranium (mislabeled here as “high-enriched”):

Iran's Highly Enriched Stockpile

So it’s quite clear that Iran has dramatically ramped up its nuclear activities, far beyond the constraints imposed on it by the JCPOA. Of course, the United States unilaterally left the nuclear agreement in May 2018.

Asked in November 2018 what the United States would do if Iran restarted its nuclear program in response, Secretary of State Mike Pompeo declared, “We’re confident the Iranians will not make that decision.”

The Iranians, in a way that was both predictable and predicted, did make that decision.

There was a great outcry at the time about the Trump administration’s decision to pull out of the deal. One leading Democratic Senator issued a statement arguing that

With this decision President Trump is risking U.S. national security, recklessly upending foundational partnerships with key U.S. allies in Europe and gambling with Israel’s security. Today’s withdrawal from the JCPOA makes it more likely Iran will restart its nuclear weapons program in the future.

That Senator? Bob Menendez.

The JCPOA wasn’t a perfect deal. It didn’t make the Iranian government into nice guys. But from a nonproliferation point of view, it was a blindingly clear success. Getting back into the exact the deal we signed in 2015 is impossible now. We’re going to wind up with something worse. Let’s not blame the deal we left for that fact.