The Gold Star father who came under attack from Donald Trump last year after offering to lend the Republican presidential candidate a copy of the Constitution sent out a fundraising email Friday for Jason Crow, a Democratic running in Colorado’s 6th Congressional District.

“Jason Crow is someone who goes where the fight is,” wrote Khizr Khan, who spoke with his wife, Ghazala, at the 2016 Democratic National Convention. The self-described “patriotic American Muslims with undivided loyalty to our country,” whose son, Army Capt. Humayun Khan, was killed by a suicide bomber in Iraq in 2004, criticized Trump’s proposal to ban Muslims from entering the United States.

Crow, a decorated Army Ranger combat veteran, is one of four Democrats running in the battleground seat held by Republican incumbent U.S. Rep. Mike Coffman, an Army and Marine Corps combat veteran.

In his fundraising email, Khan stressed Crow’s military background – something national Democrats and election forecasters have said could give Crow the edge to  unseat Coffman, who has withstood well-funded challenges from top politicians in recent cycles.

“As a former Army Ranger with years of distinguished military service under his belt, he’s shown leadership, selflessness, and immeasurable courage in the face of adversity,” Khan wrote. “We know that our country is headed down the wrong path, but if we send honorable leaders like Jason to Washington, we can start to right the ship.”

Khan’s email is only the latest in a string of appeals to help Crow’s campaign from high-profile, national Democratic figures as the quarterly fundraising deadline approaches. In addition, it’s in the wake of Crow’s addition to the Democratic Congressional Campaign Committee’s Red to Blue program providing fundraising and other support to some Democratic House candidates. Others helping Crow raise money this month have included Assistant House Minority Leader Steny Hoyer, who headlined a Crow fundraiser, and former Arizona Rep. Gabby Giffords, who sent a fundraising email.

The Khans’ brief appearance at the DNC provoked a feud with Trump that dominated the news for days.

“Hillary Clinton was right when she called my son ‘the best of America,'” Khan, who emigrated with his wife and son from the United Arab Emirates, said at the convention. “If it was up to Donald Trump, he never would have been in America.”

Khan pulled out a pocket copy of the Constitution and waved it as the crowd applauded and addressed Trump. “Let me ask you – have you even read the United States Constitution? I will gladly lend you my copy. In this document, look for the words ‘liberty’ and ‘equal protection of law.'”

Trump implied Khan’s wife had remained silent during her husband’s remarks because of her Muslim faith, saying, “She had nothing to say. She probably, maybe she wasn’t allowed to have anything to say. You tell me.”

Ghazala Khan responded that she’d been too upset to speak and fired back in an opinion article that Trump “doesn’t know what the word sacrifice means.”

Trump’s remarks the Khans drew denunciations from national GOP leaders, including Arizona Sen. John McCain, House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell, as well as prominent Colorado Republicans, including Coffman.

Coffman condemned Trump’s comments about the Khans in an interview with the New York Times.

“Having served in Iraq, I’m deeply offended when Donald Trump fails to honor the sacrifices of all of our brave soldiers who were lost in that war,” Coffman said.

Colorado’s 2016 Republican U.S. Senate nominee Darryl Glenn, a retired Air Force lieutenant colonel and a strong Trump supporter at the time – he spoke at a Trump rally in Colorado Springs the day after the Khans’ appearance at the DNC – tore into Trump, though he said the latest fracas wasn’t enough to make Glenn reconsider his endorsement.

“I completely disagree with Donald Trump’s statements; the only thing anyone should say to these Gold Star families is: thank you for your sacrifice,” Glenn said in a statement. “That said, I still believe Donald Trump would make a better president than Hillary Clinton.”

Glenn, who is among three Republicans challenging U.S. Rep. Doug Lamborn in a primary, withdrew his endorsement of Trump two months later after the “Access Hollywood” video emerged.

U.S. Sen. Cory Gardner, who hadn’t endorsed Trump at that point, issued a terse statement on the controversy without mentioning the name of the GOP presidential nominee.

“There is no room in American politics to insult our Gold Star families,” Gardner said.