The Hill | REBECCA KHEEL: Dark clouds are forming over the Iran nuclear deal as the calendar marches toward a May 12 deadline set by President Trump to improve the accord or see the United States effectively withdraw from it.

When Trump extended Iran’s sanctions relief in January, he pledged it would be the last time unless European allies agree to a supplemental deal to fix what the president sees as the fundamental problems with the nuclear pact negotiated by the Obama administration.

And while negotiations with the Europeans are ongoing, hopes for a solution are increasingly fading.

“Every single day I have a new percentage about whether we’re going to get a new deal. Today is 51/49 no deal,” said Behnam Ben Taleblu, a research fellow at the Foundation for Defense of Democracies who favors fixing the deal instead of scrapping it.

Trump came into office vowing to tear up the “worst deal ever negotiated.”

The pact signed by the United States, Iran, China, France, Russia, the United Kingdom and Germany provided Tehran with billions in sanctions relief in exchange for curbing its nuclear program.

Trump sees three main issues: several provisions sunset, inspectors can’t demand to see some military sites, and it does not address Iran’s ballistic missile program and support for terrorists.

During Trump’s first year in office, his national security team argued it was in the U.S. interest to remain in the deal — a stance that influenced Trump’s decision to decertify the deal but not to re-impose sanctions. Decertification had little bearing on the deal’s fundamentals, but re-imposing sanctions could doom it.

Now, two of the administration officials who supported staying in the deal have been ousted and are being replaced with staunch Iran hawks.

While a member of Congress in 2016, Secretary of State nominee Mike Pompeo argued that the Iran deal “virtually guaranteed that Iran will have the freedom to build an arsenal of nuclear weapons.” Following Trump’s election, Pompeo said he looked “forward to rolling back this disastrous deal.”

When announcing former Secretary of State Rex Tillerson’s firing and Pompeo’s nomination, Trump focused on the Iran deal.

“We disagreed on things,” Trump said of Tillerson. “You look at the Iran deal. I think it's terrible, I guess he felt it was OK. I wanted to break it, he felt differently.”

But it was Trump’s choice of John Bolton as his incoming national security advisor that Iran deal supporters have seen as the biggest death knell for the deal.

Bolton penned an op-ed while the deal was being negotiated that was bluntly titled, “To Stop Iran’s Bomb, Bomb Iran.” He also encouraged Trump to “abrogate the Iran nuclear deal in his first days in office” last year.

Tillerson may have been hoping for a framework agreement with the Europeans that would allow Trump to save face without killing the deal, experts said, but Pompeo and Bolton are unlikely to accept something that’s mostly symbolic.

“The views of Bolton and Pompeo matter quite a bit” to the success or failure of the European negotiations, Taleblu said. “I don’t think both of them will settle for anything that’s just crossing Ts and dotting Is.”

Since Trump’s January announcement, State Department officials led by director of policy planning Brian Hook have had several rounds of negotiations with France, the United Kingdom and Germany, the so-called E3.

Hook has said the department is preparing for either a deal with the Europeans or a withdrawal from the nuclear accord.

“We always have to prepare for any eventuality, and so we are engaged in contingency planning because it would not be responsible not to engage in it,” Hook told reporters last month after returning from Iran deal meetings in Berlin and Vienna. “We’re kind of dual-tracking this.”

Trump’s January ultimatum also included a call to Congress to pass legislation to fix the nuclear deal. But Congress’ efforts have stalled as it waits for the results of negotiations with the Europeans.

“It’s 100 percent with the administration, meaning they have to convince the E3 that there be a follow-on agreement,” Senate Foreign Relations Committee Chairman Bob Corker (R-Tenn.) told reporters last month. “If they do that, then we’ll consider legislation domestically after that occurs.”

Even if the E3 agree to sanctions for Iran’s long-range missile development, as has been discussed, the European Union Council would have to unanimously sign off on them.

Barbara Slavin, director of the Atlantic Council’s Future Iran Initiative, said there are two April dates that could determine the success of these negotiations.

The first is a mid-April EU Council meeting that could signal the EU’s response to a follow-on deal. The second is French President Emmanuel Macron’s April 24 state visit to D.C.

“That would be last chance to push a view of the deal in way that Trump might be willing to listen to because he likes Macron,” Slavin said.

Slavin also said Trump may be persuaded to renew sanctions waivers once more as Pompeo may not be confirmed by May 12 and the national security team is busy preparing for a summit with North Korea’s leader.

“This could be the argument for hanging in there,” she said. “But this is all very rational, and as we know, we have a president who gets his policy views from ‘Fox and Friends.’”

But even if Trump does not renew sanctions waivers, the deal may survive, experts said. Europe could move to protect its companies from U.S. sanctions for doing business with Iran or the Trump administration could choose not to enforce sanctions immediately, meaning Iran would still get benefits from the deal even if the United States is not a party to it.

Slavin also predicted Iran would not want to walk away from the deal immediately after the United States withdraws.

“Iran will at least initially wait to see what everyone else does,” she said.

Others were less hopeful.

“I’m quite pessimistic,” said Trita Parsi, president of the National Iranian American Council, which supports the deal.

Parsi argued Trump’s threats to kill the deal have already scared businesses away from Iran, turning Iranian opinion against the agreement.

“I think even if he doesn’t in a literal sense pull the trigger, he’s already pulled the trigger. It’s just a slow death,” said Parsi, author of “Losing an Enemy: Obama, Iran, and the Triumph of Diplomacy.” “If the Europeans had done more investment earlier on, then perhaps it would survive, but unless they really ramp up investment, it’s very difficult to see the deal survive.”