Trump and John McCain had a history of butting heads, with Trump hitting at the senator’s service in Vietnam, where he was a prisoner of war, and John McCain being the deciding vote to block a repeal of Obamacare early in Trump’s presidency. John McCain died in 2018, and in the 2020 election, the former senator’s widow, Cindy McCain, endorsed President Joe Biden over Trump.

Jimmy McCain told CNN he will be supporting Harris and that he changed his registration from independent to Democrat weeks earlier. The younger McCain also said he “would get involved in any way I could” to support Harris’s campaign.

He also took aim at Trump’s visit to Arlington National Cemetery last week, where he placed a wreath at the Tomb of the Unknown Soldier and visited graves. The former president visited on the third anniversary of 13 U.S. service members being killed in the 2021 Abbey Gate bombing during the U.S. withdrawal from Afghanistan and went at the invitation of some of the Gold Star families.

The younger McCain, who has served in the military for 17 years, said that “it just blows me away” that Trump would allegedly use the visit to advance his campaign.

“I just think that for anyone who’s done a lot of time in their uniform, they just understand that inherently — that it’s not about you there. It’s about these people who gave the ultimate sacrifice in the name of their country,” Jimmy McCain said.

John McCain had used footage of him walking through Arlington National Cemetery for an advertisement for his unsuccessful 2000 presidential campaign. The Army had said at the time that John McCain’s campaign had not received permission to film in the cemetery, and if it had asked to do so, the request would have been denied. The senator later called it a “very bad mistake.”

Footage from Trump’s visit to the cemetery last week has not been used in campaign materials but has been posted on social media accounts where Trump has posted campaign notes. Trump defended his visit, citing the invitation from the families and calling it a “beautiful day of honor.”

John McCain’s other high-profile child, Meghan McCain, has made her dislike of Trump known, but on Tuesday, she reiterated that she still identifies with the Republican Party and would not be voting for Trump or Harris in November.

“I greatly respect the wide variety of political opinions of all of my family members and love them all very much. I however, remain a proud member of the Republican Party and hope for brighter days ahead. (Not voting for Harris or Trump, hope that clears things up),” Meghan McCain said in a post on X.