According to one outside adviser briefed on the status of the talks, the negotiating team is currently working on a double-pronged “fix” that would separate Iran’s missiles into two categories: nuclear-capable long-range, intercontinental ballistic missiles that can hit Europe, and shorter-range projectiles that could hit U.S. allies and friends, including Israel, Saudi Arabia, Bahrain and the United Arab Emirates as well as American military assets.

Sanctions could be imposed for both, but those for long-range missiles would likely be harsher and kick in more automatically if Iran tested or transferred them. Those sanctions could also target Iranian entities that were exempted from penalties under the nuclear deal.

The Iran deal’s critics argue the restrictions must cover both long- and medium-range missile tests and transfers, and that the penalties for both should be just as tough. They also want all nuclear-capable missiles to be treated as part of Iran’s banned nuclear program, rather than dealt with separately.

Richard Goldberg, an Iran deal foe and former GOP congressional aide, said it was “hard to believe” that Trump would allow Iran more leniency for shorter-range missiles “that can wipe out U.S. bases and allies like Israel.”

“That’s the kind of thing his predecessor would have done in negotiations,” Goldberg said, referring to Obama.

Britain, France and Germany have agreed in principle to punishing Tehran for long-range missiles. But they’ve been sympathetic to the argument that Iran — which lacks a powerful air force — needs shorter-range missiles for legitimate self-defense, according to European diplomats. It wasn’t clear Wednesday whether the Europeans would accept the double-pronged approach on missiles, nor whether Trump himself would sign off on it.

With Iran and fellow deal members Russia and China unlikely to sign on to changes, the U.S. opted to start with the European nations, whose trade and investment Iran covets. The idea was that even if Iran doesn’t formally join the add-on agreement, the sanctions relief Tehran is receiving would be incentive enough to get it to voluntarily comply with the new terms.