Dutch politician Geert Wilders speaks with Rep. Steve King (R-Iowa) outside the Republican National Convention in Cleveland on July 19. (Peter W. Stevenson/The Washington Post)

Geert Wilders strolled toward Quicken Loans Arena, drawing the usual amount of double takes. Clad in a trim blue suit, wearing sunglasses under his silver-blond coif, he stopped to talk to Rep. Steve King (R-Iowa) and a small crowd of foreign journalists began to gather.

“He heads the Freedom Party in the Netherlands,” King explained to a delegate who was wondering about the fuss. “A little bit of controversy here and there, but who among us hasn’t created some?”

In another year, the far-right Wilders would not have made it past the Republican National Convention’s perimeter. He has proposed moratoriums on new Muslim immigration to his country and a similar halt on mosque construction. “I don’t hate Muslims,” he has said. “I hate Islam.”

But the rise and nomination of Donald Trump had inspired Wilders — and expanded his American fan base. He was just one of many people who might have been labeled extremists, and whose views are rejected by the old elite of the Republican Party, but who attended the convention and related events with a sense that their politics were finally winning.

“I was at a McDonald’s, having a hamburger, and I asked the young person who served me, ‘Are you going to vote?’ ” Wilders said. “He told me: ‘Sir, I’ve never voted, but for the first time in my life I have registered. I will vote for Trump. I feel that he’s addressing the problems.’ It’s the same that you see in the Netherlands — my party, being the strongest, is supported by the people who never voted before.”

Many members of the “alt right,” racially conscious and opposed to new immigration, came to Cleveland with the same praise of Trump’s revolution. They held meetings, co-hosted parties and happily met the news media. Richard Spencer, the president of the National Policy Institute, held a cheeky sign encouraging journalists to “interview a ‘racist.’ ” Peter Brimelow, founder of the anti-immigration and race news site VDare, stopped by a Tuesday night party headlined by Wilders.

Wilders condemned the white supremacists who kept rearing their heads and suggested that Trump do a better job vetting his retweets to prevent racists from poisoning his feed.

“I detest anything having to do with white supremacist or fascist groups,” Wilders said. “You cannot prevent that they retweet you, but I would never retweet any of that garbage myself.”

White nationalists made their presence known in Cleveland throughout the week. A scrolling ticker of tweets that wrapped around Quicken Loans Arena briefly featured one from VDare, praising a speech that criticized illegal immigration. Lori Gayne, an Illinois Trump delegate whose Twitter handle praised “white pride,” lost her credentials after a Facebook post praised “brave snipers just waiting for some “n----- to try something” at the convention.

Spencer, who was not a delegate, was nonetheless excited about the momentum he saw inside the Republican Party. On Tuesday, as he walked into the arena, he spotted the ­anti-feminist activist Daryush “Roosh V” Valizadeh using another entrance. The “alt right,” once ostracized from the GOP, was starting to find a home.

“It’s been one big, bourbon-fueled party all week,” Spencer said Thursday as he walked around one of the public protest sites near the convention. “It might be generous to say that the ‘alt right’ makes up 1 percent of the crowd here. But we’ve gone from zero to 1. I hope we can go from 1 to 100.”

The Republican Party’s mainstream, defeated by Trump, has watched the transition with horror. Sen. Jeff Flake (R-Ariz.) told the New York Times last week that Republicans needed to purge extremists, just as they once purged members of the John Birch Society. The new threat, said Flake, came from “those who want a Muslim ban, those who will disparage individuals or groups.”

For a week, those people had their run of Cleveland. The Tuesday night party, billed as a “fab” gay rights celebration, took over a dark rec center and paused for 30 minutes of speeches. Wilders was just one speaker; the event’s poster portrayed the anti-Islamist activist Pamela Geller and the provocative Breitbart editor Milo Yiannopoulos as superheroes, charging into a fight behind Trump.

All of them congratulated the hundreds of conservatives in the room for seeing that liberal Western democracy in general, and gay rights in particular, were under siege from Islam.

“We should acknowledge that Islam is the problem,” Wilders says. “No political correctness anymore. And — forgive me, to say these words — but no bulls--- about ‘radical’ Islam. Not all Muslims are radical people, but there is only one Islam, and that Islam has no place in a free society.”

After Yiannopoulos accused Democrats of betraying gay people by allowing unchecked Muslim immigration, dance music filled the room. Brimelow, standing apart from the young crowd in a three-piece suit, retreated to a quieter hallway to praise how Trump had changed Republican thinking on immigration. He had given prime convention speaking time to politicians and grieving parents to decry murders committed by undocumented immigrants.

“The Republicans wouldn’t have dared do that four years ago,” Brimelow said. “The only reason you hear it now is because Trump has blasted his way through. Even if he is destroyed, like Barry Goldwater was, Goldwater blazed a trail for Ronald Reagan. There is a blue-collar vote for these issues.”

There’s at least fresh interest in talking about those issues, and celebrity for anyone who does. Wherever Wilders went in Quicken Loans Arena, he was pursued by reporters who wanted to know how Europe felt about Trump. On the floor, Wilders was repeatedly approached for autographs by delegates who had seen him on Fox News, or read his articles. Again and again, they delighted over the success of someone who laughed and fought harder when the old media gatekeepers called them racist or extreme.

“They’ve about used up their ammo, throwing that ‘racist’ word out,” said King, the representative from Iowa. “They’ve cheapened it. They’re going to have to come up with something else.”