WASHINGTON – Matthew Miller, 25, didn’t know how his family would react when he decided to tell them he is gay.

He certainly didn’t expect, five years later, to take a road trip to Indiana with his father – a Republican who proudly slapped a “Pete 2020” bumper sticker on his car – to witness Pete Buttigieg, the first openly gay Democratic candidate for president, officially kick off his campaign.

“My dad and I thought it would be a great moment to share together,” Miller told USA TODAY before departing from upstate New York.

Because both had to work Saturday, they planned to drive overnight to arrive at South Bend around 3 a.m. Sunday. To help keep them awake, they had the “buttijam” playlist that Buttigieg’s husband, Chasten, posted on social media Friday for all the road warriors.

Miller expected to grab only a few hours sleep before lining up by at least 8 a.m. for Buttigieg’s 2 p.m. announcement, which is expected to draw 10,000 people.

If there’s time after, Miller said, he and his father might grab a bite at the restaurant where Pete and Chasten had their first date.

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Miller is not supporting Buttigieg just because he’s gay. He calls that the “cherry on top of the ice cream.”

He also likes Buttigieg’s youth, the fact that he’s a fellow veteran and what he calls Buttigieg's calm manner of breaking down politics in an easy way to understand.

“He’s representing so many different communities that haven’t been really represented before,” Miller said. “It’s a once-in-a-lifetime thing that you just have to be there for to experience.”

But Sunday’s event is particularly meaningful to members of the LGBTQ community who are aware that it was only about 20 years ago when Matthew Shepherd, a gay student in Wyoming, was kidnapped and killed.

Mark Meier, a 23-year-old communications associate from Washington, D.C., marvels at the progress.

After being inspired by Buttigieg’s unsuccessful 2017 bid to head the Democratic National Committee, Meier tried to push things further through a grassroots effort to encourage Buttigieg to run for president.

“Not many people knew who he was and a lot of people thought it was crazy that he would run,” Meier said. “We still have a few people who think it’s crazy that he’s running. But not nearly as many.”

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In fact, Buttigieg has been the surprise candidate at this early stage of the race, vaulting over more established Democrats in fundraising and in polling in the early-voting states of New Hampshire and Iowa.

The LGBTQ community has helped Buttigieg get to this point through fundraising and spreading the word. But even they’ve been caught off guard by how quickly he’s taken off.

“There’s something going on across this country that’s surprising and amazing and wonderful,” Annise Parker, head of the LGBTQ Victory Fund, said before introducing Buttigieg at a recent fundraiser for the group.

In January, Miller stumbled across Buttigieg’s video announcement of his exploratory candidacy and was “completely inspired,” even though he didn’t initially realize that Buttigieg is gay.

“I was just completely caught off guard in a good way,” he said. “I was like, holy cow. This is amazing.”

Miller started contributing to Buttigieg’s campaign, wearing "Pete" buttons to Democratic events, hosting watch parties for campaign events and encouraging others to give to Buttigieg by raffling off copies of Buttigieg’s memoir to supporters who could show they had donated to the campaign.

Miller’s father, whom his son describes as a “staunch Republican,” was captured by the message of pragmatism he heard from Buttigieg.

Growing up, Miller had heard family members make homophobic remarks and say they didn’t support the gay “lifestyle.”

When Miller did come out, his family fully backed him. But it took time to adjust, especially for his father, he said.

Now, that's all in the past.

"Thank you Mayor Pete and Chasten for giving us all hope," Miller tweeted Saturday, "but most importantly, thank you for making the bond between my dad and I even stronger."