As D.C. Mayor Muriel Bowser stepped off a Mike Bloomberg presidential campaign bus Sunday night and darted through the dark into an Arlington, Va., field office, she passed a crowd of angry protesters jeering at her on the sidewalk.

Holding signs like “WE WILL NOT COMPLY,” dozens of booing gun-rights activists railed against “Mini Mike”—the former mayor of New York City now seeking the Democratic presidential nomination—and his nationwide push for restrictions on firearms. They waved the Stars and Stripes, hoisted the “DONT TREAD ON ME” Gadsden flag, and chanted Virginia’s state motto, “Sic semper tyrannis,” as an ominous warning to would-be tyrants.

“When we got off the bus I thought we might be in the wrong place,” a smiling Bowser told at least a hundred people in the Bloomberg office a few minutes later, “because they told me Virginia is for lovers.”

Bowser delivered her remarks on stage next to a bright white column decorated with wavy stripes of light blue and red — a polished, patriotic display evoking the corporate logo of Aquafresh toothpaste. She said she hoped that “next January we’re going to have a big parade down Pennsylvania Avenue in my town” to celebrate Bloomberg’s inauguration.

The D.C. mayor announced her endorsement of Bloomberg last month, praising his plans for affordable housing when they appeared together at the Atlas Performing Arts Center on H Street in D.C. Sunday’s campaign event—following similar stops Bowser made in Hampton Roads and Richmond earlier in the day—came less than a month after Bloomberg praised the D.C. mayor’s leadership in a speech to the U.S. Conference of Mayors.

“I think this city’s future is brighter than ever, and a lot of the credit goes to my good friend Mayor Muriel Bowser,” he told the gathering. “She is doing a terrific job, and I hope someday soon we’ll be calling her ‘Governor Bowser.’ I do think the time has come for D.C. to become a state with full voting rights, and as president I’ll work with Congress to make that happen.”

Bloomberg even made a point of comparing Bowser favorably to the current president. “There are two elected executives in Washington—the president and the mayor,” he said in a statement. “One has broken promise after promise on the issues that matter. The other has emerged as a national leader on affordable housing, economic opportunity, sustainability, safe streets, good schools, and equal rights—and that’s Mayor Bowser. Washington, D.C. could not be in better hands, but she and local leaders around the country deserve a true partner in the White House—and that’s what I’ll be.”

Bowser may be an ally, but the moderate, business-friendly candidate has generated plenty of controversy in his race for the presidency. Having already drawn on his personal wealth to spend a quarter billion dollars on political advertising, Bloomberg faces criticism that he’s a billionaire “trying to buy the election,” in the words of a campaign memo from frontrunning rival candidate Sen. Bernie Sanders. It was telling that, among other slogans, the protesters outside the Arlington office chanted “you can’t buy the election.”

Yet Sunday’s demonstrators were a reminder of another way Bloomberg has used his fortune—bankrolling the national gun-control advocacy group Everytown for Gun Safety, which last year outspent the gun-rights behemoth National Rifle Association roughly 8-to-1 in Virginia and aided a Democratic takeover of the state legislature. This move endeared him to Democrats, for whom he’s now a kind of political giant slayer in the raging culture war over the Second Amendment. But it also solidified him as a reviled figure among conservatives, who already saw him as the meddling government “nanny” trying to ban large sodas in New York.

“These New York politicians need to stay out of Virginia,” bellowed Republican U.S. Senate candidate and U.S. Army reservist Tom Speciale, addressing Sunday’s protest with a bullhorn. “This last year they spent millions of dollars buying our school boards and buying our local politicians with their filthy money from New York, California, Florida, and Pennsylvania. We do not want New York values in Virginia. This is where liberty was born into the world and we will defend liberty again if we have to.”

Bloomberg supporters talk about a different kind of liberty—the right to live free of gun violence. Bowser was joined at Sunday’s events by survivors of gun violence and the families of shooting victims, all of whom cast the former New York City mayor as a champion of their cause.

“We know that we can do better,” Bowser said, “that we can have common-sense gun regulations and responsible gun owners can have their guns. We know that Americans support universal background checks. We know that Americans want to close gun-show loopholes.” She said city leaders can take local actions on their own, but “can’t stop illegal-crime guns from coming across our borders in states that won’t regulate them.”

By the time Sunday’s Bloomberg event wound down, the protest outside had grown to a crowd of hundreds. The right-wing demonstrators continued to boo loudly, shouting “shame” as Democrats filed out of the building. It was proof of one thing Bowser had told gun-control advocates: “They’re not going to give it to us.” Winning change would require “those tough conversations with your neighbors and friends,” the mayor said.

In a final demonstration of the conservative resistance, Speciale and another gun-rights activist managed to slip inside the Bloomberg event after the speaking program. They even addressed the room briefly from the podium before the soundsystem drowned them out with “Praise You” by Fatboy Slim. “Our hearts go out to anyone who’s lost somebody to gun violence,” Speciale said, “Those people out there will protect your rights, regardless….I know you don’t want to hear it, but it’s a reality!”

Bowser appears ready for the long fight — both for Bloomberg in 2020 and on the issue of gun violence. In fact, her prominence in Bloomberg’s campaign has raised the prospect that she could have a role in his presidential administration, perhaps even as vice president. But when DCist tried to gauge her interest, she fell back on a familiar refrain. “I have the best job in Washington, D.C. I’m the mayor of my hometown,” she said, before immediately ending the interview.