President Trump announced his candidacy four years ago Sunday to the cheers of paid actors in Trump Tower and to the horror of many conservative leaders, who vowed to defeat him.

On Tuesday, Trump will launch his reelection bid before about 20,000 supporters in a Florida arena, and to applause from many former skeptics who say they misjudged him.

In 2016, Trump nearly toppled the Republican “big tent.” Wide-eyed social conservatives noted he used to back abortion rights. Security hawks gaped at dovish remarks on the Mideast and Russia. Free-market conservatives called him a protectionist who supported single-payer healthcare.

But as president, Trump has quieted concerns, winning deep tax cuts, appointing conservative judges, and renegotiating the North American Free Trade Agreement, while wowing hawks by moving the U.S. Embassy in Israel and withdrawing from the Iran nuclear deal.

“Who would have thought a supporter of Planned Parenthood would be the strongest pro-life president in history?” marveled Brent Bozell, the Media Research Center president and nephew of conservative icon William F. Buckley. “At the end of the day I think that Trump has done more for the concept of American exceptionalism than any president since Ronald Reagan.”

In 2016, Bozell contributed to the conservative National Review’s “Never Trump” edition, an effort to halt Trump’s momentum in the Republican primaries, featuring condemnation from Glenn Beck, Bill Kristol, Dana Loesch, and others.

“I think that people were looking at his record, which was in the opposite direction of the rhetoric, and a lot of people were Doubting Thomases,” Bozell told the Washington Examiner.

For the magazine, Bozell wrote that “Trump might be the greatest charlatan of them all,” expanding on Fox News that Trump was “a shameless self-promoter, a huckster.”

“God help this country if this man were president and he continued on in this way,” Bozell exclaimed at the time.

Many, but not all, of Bozell’s fellow Trump skeptics have changed their tune, including Loesch, a syndicated radio host and author, who scoffed in 2016 at Trump's recent "conversion" to conservatism and worried about his business dealings.

"He has checked so many boxes for conservatives and Republicans, I don't know how anyone can be dissatisfied," Loesch said, praising Trump's rollback of regulations, support for the military, and the roaring economy.

"With all of my concerns, I was really hoping to be wrong. I wasn't one of those individuals so self-centered I hoped the country would do poorly," said Loesch, who works with the National Rifle Association but commented in a personal capacity.

Sen. Lindsey Graham, R-S.C., one of Trump’s former critics on national security issues, said Friday that Trump "has exceeded every expectation I had."

“I ran out of things to say about him in the campaign. I voted for somebody I wouldn’t know if they walked in the door, Ed McMullin," Graham told conservative radio host Hugh Hewitt, another former skeptic.

“Everything that you and I and people who were pooh-poohing Trump about, he’s proven to have risen to the occasion, to be a commander in chief that has our military’s back, that I respect,” Graham said, citing the defeat of ISIS in Iraq and Syria and new military funding.

The feeling isn't universal. Trump’s conservative independent challenger in 2016, Evan McMullin, whose name Graham garbled, is pushing for impeachment proceedings over Trump allegedly obstructing special counsel Robert Mueller’s investigation.

“Too many in Congress, both Republicans and Democrats, are letting partisan politics get in the way of doing the right thing,” the ex-CIA operative said recently.

Bozell said some Never Trumpers “are so offended by his personality and what they would see as a lack of decorum that I don’t think they will ever support him.”

Indeed, some conversions were slow. Beck last year said he would back Trump for reelection. Erick Erickson, editor of The Resurgent, got a call from Trump in January praising him for an article he wrote about a proposed border wall. Weeks later, Erickson declared, “I will vote for Donald Trump."

Bozell said that despite his own criticism in 2016, he actually urged Trump to run in early 2015, before realizing to his disbelief that Trump was catching fire with the electorate. He thought Trump would lose but make a dent in the landscape. “I didn’t think he could win. But ... I thought he might win in the future if he got out his dirty laundry,” Bozell said.

Loesch said she advises fellow conservatives that "if you have a problem with Trump the person, you have to look at the issues. How are your issues being advanced?"

"This is an avatar for our issues," she said of Trump.