Secretary of State John F. Kerry, left, at a news conference with French Foreign Minister Laurent Fabius on Saturday after consultations on the status of nuclear negotiations with Iran. (Evan Vucci/AP)

There are many words being bandied about to describe the deal likely to emerge from the world’s most talked-about diplomatic negotiations — the ones focused on Iran’s nuclear program.

Try a “framework,” an “agreement” or an “understanding.”

Just don’t call it a “treaty.”

The name for a still-in-the-works deal between Iran and six other countries, including the United States, is more than a matter of linguistics.

Secretary of State John F. Kerry acknowledged as much this week when he told a Senate hearing, “We’re not negotiating a, quote, ‘legally binding plan’ ” with Iran.

Graphic: Iran's potential nuclear capability

The advantage — or disadvantage, depending on your point of view — of keeping a possible deal in a not-legally-binding box is that it doesn’t require the review and approval of the Senate, as a treaty would.

The administration and supporters of a deal say keeping it away from the Senate is a practical step, ensuring it can be implemented immediately and is flexible enough for some quick tweaks if Iran tries to cheat. Critics say it’s an end run around the Senate’s advice and consent role.

What it does not appear to do, however, is make it any more or less likely that the parties will live up to their commitments. In Iran’s case, that means accepting limits and probes of its nuclear program in exchange for some relief from sanctions.

“These happen all the time,” said Tyler Cullis, a lawyer specializing in sanctions for the National Iranian American Council, an independent group based in Washington. “In most cases, the expectation in a nonbinding agreement is the same as in a legally binding one.”

Some of the more famous and expansive deals in American history also have not been legally binding.

The Helsinki Accords of 1975, under President Gerald R. Ford, set events in motion that forced widespread political and social changes in the Eastern Bloc. The Shanghai Conference in 1972, announced when President Richard M. Nixon made his historic visit to China, opened the door to normalized relations. The Atlantic Charter of 1941, under President Franklin D. Roosevelt, paved the way for numerous agreements that followed World War II.

More recently, last year’s announcement between China and the United States united the two countries in combating climate change.

“The overriding reason to prefer a nonbinding international arrangement to a treaty is the need to preserve the greatest possible flexibility to reimpose sanctions if we believe Iran is not meeting its commitments,” said State Department spokeswoman Jen Psaki.

Richard Nephew, until recently the deputy coordinator of sanctions policy at the State Department and now a scholar at Columbia University, said legally binding treaties and some executive agreements requiring Senate review take 180 days to implement, and additional delay if sanctions, once eased, have to be reimposed in case of a breach.

“At the end of the day, it’s still politically binding,” he said. “Commitments are made. What’s the real consequence to Iran? If it were a treaty or legally binding and they violate it, that has significance. But the bigger impact is sanctions will be reimposed. If we don’t fulfill our part, Iran’s nuclear program will expand. That’s still a consequence, just more practical than legal.”

But critics see the approach as a deliberate attempt to skirt the Senate, take it to the U.N. Security Council for a vote on lifting international sanctions, and then present it to the Senate as a fait accompli.

“They’re trying to structure something so Congress will have no role, and a future president will find it difficult to walk away from it,” said Mark Dubowitz, executive director of the Foundation for Defense of Democracies. “The administration will be using the force of international law to override constitutional prerogative. . . . It’s ingenious and, depending on your perspective, devious.”

At this point, the debate is theoretical. Kerry will return to Switzerland on Sunday to lead the American negotiating team as it resumes talks with Iran. Negotiators have said they aim to have a framework, or an agreement, or an understanding, by the end of March.