CALL IT an international-relations reality check.
A former member of the US Senate himself, John Kerry is fine with Congress having a role in any nuclear deal the Obama administration and the international community strikes with Iran.
But the US secretary of state stresses that the choice the United States faces won't be between this (still tentative) pact and an even tougher deal. The choice will be this deal or no deal.
"Look, if Russia, China, Germany, France, and Britain, all of whom have nuclear programs, sign off on this, and all their experts say it's a good deal, and Congress for political reasons wants to go kill it, they're walking away," Kerry says of the other parties to the negotiations.
And if they do walk away, Kerry said during a Sunday sit-down at his Beacon Hill home, that would spell the end of the international sanctions regime on Iran.
"There will be no sanctions, because none of them will enforce sanctions if they think we had a reasonable deal, but only the Congress decides no," Kerry said. In that circumstance, the United States won't be able to keep the P5+1 nations (the five permanent members of the UN Security Council plus Germany) together for such an effort, Kerry says.
Which leads to the secretary of state's bottom line. "The whole mythology I've heard, from [Israeli Prime Minister Benjamin] Netanyahu to Republican members of the House and Senate — 'Oh, just squeeze them to death, raise the sanctions' — not gonna happen," he concludes.
Obviously the details, which must be thrashed out by June 30, are critically important. For now, Kerry isn't hugely concerned about the somewhat different Iranian statements on the framework.
"If it's not what we believe we agreed to and if it's not what we have to have, we won't sign a deal," he declares.
Partisan critics and Republican presidential candidates may scoff, but what the Kerry-led effort has accomplished so far is impressive. The framework agreed to earlier this month was tougher, more comprehensive, and with a greater level of inspections than many had thought possible.
It would markedly reduce the number of Iran's operational uranium-enrichment centrifuges for 10 years; limit enrichment to reactor-fuel level (well below weapons grade) and decrease Iran's stores of that uranium by 98 percent for 15 years; reconfigure its heavy-water reactor so it can't produce weapons-grade plutonium; and give the International Atomic Energy Agency regular inspections access to Iran's nuclear facilities.
If implemented, then, the pact would address the most problematic parts of Iran's nuclear program. That's why the reaction from nonproliferation experts has been largely favorable.
In our interview, Kerry stressed an aspect of the framework that has gotten less attention: the close scrutiny the IAEA will bring to bear on the entirety of Iran's nuclear-fuel cycle.
"We got 25 years — a hell of a long time — of everyday inspection of the entire fuel cycle, all of their uranium, from the mine to the mill to the yellowcake to the gas to the centrifuge, out into waste," he said.
Jeffrey Lewis, a nonproliferation expert at the Middlebury Institute of International Studies at Monterey, says that if the final agreement is true to the framework, the extensiveness of the inspections "would make it very hard for them to construct a covert facility," always a significant concern in attempts to curtail nuclear-weapons programs.
If and when Congress weighs in, any final agreement should be judged against both the pre-negotiation situation and that which might ensue without the deal.
There, one point in particular stands out: The provisions of the tentative deal would lengthen from a couple of months to at least a year the period it would take Iran to produce enough fissile material to make one bomb. (The so-called "break-out" period doesn't include the time to turn the nuclear material into a weapon.)
"If we saw them moving towards that, which we will [be able to], we will then be able to move first back to sanctions if we want to, or immediately to a military option," Kerry notes.
Which is to say, compared to the alternatives, the risks we will be taking with this deal are not huge. The potential rewards, however, are.
That's why, on this vital matter, reflexive partisanship should stop at the water's edge.
Scot Lehigh can be reached at firstname.lastname@example.org. Follow him on Twitter @GlobeScotLehigh.
• John Kerry: A critical deal, but more work to be done
• Michael A. Cohen: Deal an example of how foreign policy should be conducted
• Alan Berger: What Israel, Saudi Arabia really mean when they criticize deal
• Nicholas Burns: The deal's rare achievement
• Kaveh L. Afrasiabi and Nader Entessar: Nuclear deal could reset US-Iran relations
• Colin Nickerson: Can the US-Iran rift be healed?