Over the last few weeks, the fate of Donald Trump’s presidency, the global economy, and millions of American lives have hinged on the man who executive-produced The Lego Movie.

That man, Treasury Secretary Steven T. Mnuchin, might seem like an unusual point person to handle the widespread fallout of a global pandemic. But it’s an unusual moment, and Mnuchin—personally tasked by President Trump to represent him in high-stakes congressional negotiations over coronavirus legislation—has seemingly met it, earning the trust of both parties on Capitol Hill while so far retaining the confidence of his famously mercurial boss.

Over the past week, as bipartisan talks in the Senate over a trillion-dollar coronavirus relief bill broke down into angry finger-pointing, it was Mnuchin who seemed almost above the fray, serving as a go-between for the two sides.

“Part of power is title, part is knowledge, and part is situation,” said Jack Kingston, the former congressman and current Trump surrogate. “And [Mnuchin] checked all three boxes.”

By the time a deal was reached on a $2 trillion bill to respond to the coronavirus outbreak, a rare show of affection between the Trump White House and Capitol Hill Democrats was on display: Senate Minority Leader Chuck Schumer (D-N.Y.) pointedly noted in a Wednesday letter that he had been “working hard on a bipartisan bill with Treasury Secretary Steven Mnuchin and President Trump.” Later, at the White House, Mnuchin effusively praised Democrats’ work on the package and the “enormous bipartisan support” it had.

Democrats and administration officials were impressed at the final product. Many congressional Republicans were satisfied; some didn’t love what was in it; but the majority seemed simply relieved that Mnuchin was able to land the proverbial plane at a time when few can.

“He has Trump’s ear and he can steer the president,” said a senior House GOP aide. “That’s important and something he has that McConnell or most Senate Republicans can’t claim.”

That Trump—infamous for believing in his own brilliance—would entrust the fate of his presidency to Mnuchin is due, in large part, to a sense that Mnuchin’s motivations don’t conflict with his own.

In conversations with various confidants and aides over the years, the president has frequently commended Mnuchin as someone who’s been steadfastly “loyal,” the single trait Trump values most in a top official or cabinet secretary. During the 2016 presidential run, the future president would tell people when introducing them to Mnuchin that he makes “the greatest movies in Hollywood” and how much Trump had enjoyed watching with his grandchildren a kids’ movie that Mnuchin had helped finance.

“During the 2016 campaign and since he became president, I’ve repeatedly heard President Trump refer to Mnuchin as a ‘smart guy,’ a ‘winner’ who makes the ‘best deals,’ in finance and in Hollywood,” recalled Jason Miller, a former senior Trump adviser. “It is not surprising to me that the president is entrusting the secretary with what could be one of the defining moments of his presidency.”

During the course of talks around a coronavirus-related economic package, Trump essentially took a back seat to his treasury secretary, aside from check-in calls with the congressional principals. The sheer size of the package dwarfs any other modern stimulative measure. And it contains provisions that are poised to increase Mnuchin’s own power dramatically. The treasury secretary will have control of a $500 billion pot of loans to companies hit hardest by the coronavirus—which he can award to the companies of his choosing.

By Friday, that power had grown only greater after Trump signed an executive order allowing him to override a requirement that the inspector overseeing implementation of the new corporate fund report to Congress if he or she is not given information by the administration. Perhaps, it dawned on some Democrats, Mnuchin wasn’t to be trusted after all.

“If I were Secretary Mnuchin I would start thinking about another line of work because he has just blown whatever credibility he built up with congressional Democrats,” said Jim Manley, the former top spokesman for former Senate Majority Leader Harry Reid (D-NV). “This little bit of treachery is going to have lasting consequences.”

Mnuchin’s path to becoming a trusted broker for a government in crisis was not obvious, and it was bumpy at times. The secretary’s earlier engagements with congressional Democrats have been acrimonious, especially during the last time Mnuchin was a major player on the Hill: pushing for Trump’s 2017 tax cut bill.

While the tax-cut effort was highly partisan and few expected it to earn Democratic votes—nor were they needed in order to become law—Hill Democrats recall radio silence from Mnuchin during that time, aside from a perfunctory call or two.

“In some ways, it’s all relative with Mnuchin because we obviously, vividly remember how the ’17 tax bill went down,” said one Democratic aide.

Whatever lingering bitterness there was seemed to disappear as talks over the first emergency bill to counter the coronavirus began last month. Democrats appeared to warm to Mnuchin as a rare commodity in the Trump administration: a high-level figure who actually seems to speak for Trump, is far less ideological than his peers, and instead shares his boss’ instinct to cut deals. And it’s not lost on some of them that the former investment banker and Hollywood mogul has, at the very least, some Democratic sympathies—he cut a check for Kamala Harris’ first Senate campaign in California in 2016.

“Obviously, he’s a wealthy guy, he doesn’t wanna pay taxes,” said a Democratic aide of Mnuchin, “but I don’t think he’s ideological in the same way [former chief of staff] Mick Mulvaney is. You can deal with him in a way you can’t deal with other members of the administration.”

To some Republicans, that perception became a source of anxiety during the marathon negotiations over coronavirus relief. The previous coronavirus bill, which passed last week and largely focused on shoring up the nation’s health care system, was negotiated primarily between Mnuchin and Speaker Nancy Pelosi (D-CA). When those talks produced a bill many Senate Republicans panned, McConnell urged them to vote for it anyway and shift their focus to the third coronavirus bill.

Yet again, though, the main interlopers on that bill ended up being a Democrat and Mnuchin. When talks between McConnell and Schumer broke down over the weekend, the secretary continued talks with the Democratic leader.

Some Republicans watched anxiously as Mnuchin and Schumer huddled for several lengthy negotiating sessions on Capitol Hill, worried that him staying at the table as long as he did gave Democrats even more leverage. On Tuesday night, Sen. Lindsey Graham (R-S.C.) took to the Senate floor to publicly beg Trump to yank Mnuchin and to tell Democrats to take what they’d worked on or leave it.

Other Republicans fretted about what Mnuchin—whom people in both parties describe as a dealmaker, not someone concerned with the weeds of policy—might concede to Democrats in the name of getting something done.

“I think the longer that Mnuchin stayed at the table, the less likely it was that McConnell would have been able to undercut him,” said a Republican source.

But at that point, said some, Mnuchin of all people was best situated to bring the bill home.

“If Chuck and Nancy are going to be difficult, we need someone who can handle that,” said a Senate Republican aide. “It clearly got to a point where it was more beneficial for Mnuchin to be the one doing that and maybe to be the slightly disinterested third person, compared to having McConnell and Schumer in a room.”

—with additional reporting from Asawin Suebsaeng and Sam Stein