WASHINGTON – With less than one month to go before a White House deadline to “fix or nix” the Iran nuclear deal, US diplomats remain without a leader at the State Department, and US allies in Europe remain unclear on what they can do to prevent President Donald Trump from withdrawing from the accord.

Trump set out a May 12 deadline for his diplomats to negotiate a supplemental agreement with Britain, France and Germany that would impose strict new terms on the 2015 nuclear deal. While the “E3” powers have been willing to engage the Americans on ways to address Iran’s regional power projection and its ballistic missile work, they have thus far rejected any moves that would violate or rewrite the nuclear deal itself.

French President Emmanuel Macron will visit the White House next week as the honored guest of Trump’s first official state visit, and the Iran deal is expected to top their agenda, senior administration officials say. Macron and Trump have grown close over the last year, and the French president’s personal appeal is seen by advocates of the deal as its best hope of survival.

Federica Mogherini, the EU’s high representative for foreign affairs, said on Monday that the union offered “support for the work that in particular France, Germany and the UK are developing with the US administration to address some of the concerns that President Trump has expressed within the framework of the existing agreement.”

Macron said last week that he successfully convinced Trump to keep a US troop presence in Syria – an example of their cooperative relationship, according to the Élysée Palace. But reports emerged on Monday that, in fact, Trump is still working to replace US troops there with an allied Arab presence.

And Macron has failed to influence Trump on other major policy actions in the past. Despite repeated pleas, for example, Trump defied him and the rest of the world by withdrawing from the Paris climate accord last year.

Macron would like to see the Iran deal remain intact, although he has signaled he shares some of the US’s concerns with the accord, including its inclusion of sunset clauses that allow Iran to legitimately restart much of its uranium enrichment work in less than a decade.

European leaders and diplomats believe their best hope for salvaging the deal is in lobbying Trump himself, because his State Department remains rudderless and detached from the president’s thinking.

The Senate is scheduled next week to vote on Trump’s choice for secretary of state, Mike Pompeo, who, if confirmed, would succeed Rex Tillerson. Trump fired Tillerson on Twitter last month, in part over disagreements on the nuclear deal, the president said at the time.

In his Senate confirmation hearing, Pompeo refused to clarify his position on the agreement, or on a US withdrawal, only stating that he would prefer a diplomatic fix.

“If there’s no chance that we can fix it, I will recommend to the president that we will do our level best to work with our allies to achieve a better outcome and a better deal, even after May 12,” Pompeo said.