During arms negotiations with Soviet leader Mikhail Gorbachev, Ronald Reagan was fond of quoting a Russian proverb that means “trust but verify.”

When he said it again at the signing of the Intermediate-Range Nuclear Forces Treaty in December 1987, Gorbachev remarked, “You repeat that at every meeting.” Reagan replied, “I like it.”

How do you say trust but verify in Persian? For the truth is, the framework for a nuclear deal with Iran is only partly about the technical details. It is also a matter of trust.

Assuming a final agreement really resembles what the State Department outlined publicly, it will have its weaknesses. Iran will remain a nuclear threshold state. The Islamic republic will be allowed to maintain a vast nuclear infrastructure, and the deal’s success depends on the “P5+1” group’s ability to detect and penalize Iranian cheating in a timely fashion.

There’s nothing in the agreement that will stop Iran from being a bad actor, a country that funds terrorism and threatens Israel. Yet it is precisely these facts about the Iranian regime’s character that make us so concerned about restricting its nuclear program in the first place.

The deal has to be evaluated against plausible alternatives, not an ideal outcome. It was in the absence of any deal that Iran went from having a little over 16o centrifuges in 2003 to 3,000 in 2005, 8,000 by the beginning of Barack Obama’s presidency and 22,000 by 2013.

If Iran abides by the terms of the framework, it will reduce the number of centrifuges to closer to 6,000. Not great, but a better trajectory than the past decade. And it casts doubt on the main nonmilitary alternative to the deal, which is to slap on some more sanctions and hope for the best.

That’s assuming the multilateral sanctions regime will even remain in place if the deal is blown up at this point. If Iran is responsible for the end of the talks, international pressure can likely be sustained. But if the United States is seen as the party walking away, expect Russia and China to do more business with Tehran.

Of course, another option is war. Critics of the deal don’t like it when it is suggested that the failure of diplomacy makes war more likely. They borrow one of Obama’s favorite catchphrases and call it a “false choice.”

This would be more convincing if leading Iran hawks weren’t already calling for bombing Iran or saying war is our best option. Others suggest we should at least make threatening war a more prominent part of our bargaining posture. Some members of Congress have floated authorizing the use of military force.

Bombing Iran would probably blow up the multilateral sanctions and end any inspections while driving the country’s nuclear program underground. Actually stopping the nuclear program militarily would likely require more than a few airstrikes.

Former Defense Secretary Robert Gates has been quoted as saying, “If you think the war in Iraq was hard, an attack on Iran would, in my opinion, be a catastrophe.”

At the end of the day, however, Obama has to convince members of Congress that Iran can be trusted to comply with the deal. Ever since the 1979 hostage crisis, trusting the ayatollahs has been a tough sell.

Compounding this problem is that many lawmakers don’t trust Obama. On the issue of Iran’s nuclear program, that includes some Democrats as well as Republicans.

The recently indicted Robert Menendez is being replaced as ranking Democrat on the Senate Foreign Relations Committee, but fellow Democratic Iran hawk Charles Schumer is the frontrunner to replace Harry Reid as caucus leader. Ben Cardin, the Maryland Democrat taking over Menendez’s committee duties, is something of a wild card.

You would think the trustworthiness of the some of the most hawkish voices would have been settled by the Iraq war, which accomplished nearly the opposite of what was promised prior to the 2003 invasion, but you would be wrong.

Can Obama gain enough congressional confidence to at least sustain a veto of legislation that would make it difficult to consummate a deal?

It all comes back to Reagan’s farewell address. “It’s still trust but verify,” he said. “It’s still play, but cut the cards. It’s still watch closely. And don’t be afraid to see what you see.”

What will we see at the end of June?

W. James Antle III is managing editor of the Daily Caller and author of Devouring Freedom: Can Big Government Ever Be Stopped?