It wasn’t that long ago that Peter Navarro was the butt of jokes in Washington.

Now, or at least for the moment in the topsy-turvy world of the Trump White House, it looks like he just got the last laugh.

Navarro, a trade deficit hawk, has long advocated for President Donald Trump to impose trade restrictions on national security grounds and to pull out of the North American Free Trade Agreement.

Read archived story: White House’s Navarro says tougher trade stance would only result in ‘modest’ inflation

His primary opponent within the White House has been Gary Cohn, the president’s pro-trade head of the National Economic Council.

The two have jockeyed for Trump’s attention, with Cohn initially coming out on top.

But the balance of power shifted dramatically toward Navarro last week when Trump announced the U.S. would set tariffs of 25% for steel and 10% for aluminum, sparking concerns of global trade wars.

Unable to change Trump’s mind about the tariffs, Cohn announced his resignation late Tuesday.

Read:Trump’s economic adviser Gary Cohn resigns after losing tariff fight

A trade publication recently suggested that Navarro is set for a promotion into Trump’s inner circle.

Simon Johnson, a professor at the MIT Sloan School of Management, said the concern is that Navarro will push Trump to “step outside” the multilateral trade system, including the World Trade Organization that was designed and built by the U.S. after World War II.

See: Trump tariffs may really be a backdoor way to get out of the WTO

“The irony is not that we built and were central to the creation of the multilateral trade system but that it was deliberately, 100% built entirely with the goal of America first,” Johnson said.

“It was in the interest of the U.S. to set up market economies with relatively free and open trade as a counterweight to the Soviet Union,” he said.

Read:Trump steel tariffs to hit these 8 countries the hardest — and China isn’t one of them

Navarro, 68, is a Harvard-trained economist who moved out to the West Coast to make a career. After a few unsuccessful attempts to run for political office, he made a career writing economic books for mainstream audiences while teaching at the University of California, Irvine.

After the turn of the millennium, Navarro started to concentrate on warning about the threat from the rise of China. This brought him to the attention of Trump, and the two re-connected when the businessman launched his presidential campaign.

During the election, Trump at one point touted a 45% tariff on imports from China.

After the election, Navarro came to White House but had trouble finding influence, appearing to fall out of favor.

But he stayed out of the spotlight and is seen as ascendant as many other close advisers have departed the White House.

“Reports used to depict Mr. Navarro as stalking the halls near the Oval Office waiting for opportune moments to slip in and bend the President’s ear. Apparently, he succeeded,” wrote Lawrence Martin, writing in Canada’s Globe and Mail, who called him “Ottawa’s worst nightmare.”

Another factor aiding Navarro is that the American elite is starting to doubt its long-standing approach of coddling China, according to a report in the New York Times, in part from China’s decision to allow Xi Jinping to serve as president indefinitely.