CHICAGO (NewsNation Now) —Democratic Presidential candidate Joe Biden announced Tuesday that Cindy McCain plans to endorse him because of President Trump’s remarks about service members.

“Maybe I shouldn’t say it but I’m about to go on one of these Zooms with John McCain’s wife, who is first time ever is endorsing me because of what he talks about with my son and John’s who are heroes, who served their country, you know he said they’re losers, they’re suckers,” Biden said.

Biden was referring to comments Trump reportedly made mocking the American war dead. Trump has denied making the remarks, first reported through anonymous sources by The Atlantic, but many of the comments were later confirmed by The Associated Press.

On Tuesday evening, Cindy McCain took to Twitter to show her support of Biden with a series of tweets:

“My husband John lived by a code: country first. We are Republicans, yes, but Americans foremost. There’s only one candidate in this race who stands up for our values as a nation, and that is Joe Biden. Joe and I don’t always agree on the issues, and I know he and John certainly had some passionate arguments, but he is a good and honest man. He will lead us with dignity. He will be a commander in chief that the finest fighting force in the history of the world can depend on, because he knows what it is like to send a child off to fight.”

The late Sen. John McCain’s widow Cindy could help Biden appeal to Republicans disaffected with the GOP president and give the former vice president a boost in Arizona, a crucial swing state that McCain represented in Congress for 35 years.

Trump has had a fraught relationship with members of John McCain’s family since he disparaged the Arizona senator during his 2016 campaign. But the McCains have stopped short of endorsing Trump’s rivals.

Before the formal endorsement, Cindy McCain already had gone to bat for Biden’s presidential run. She lent her voice to a video that aired during the Democratic National Convention and was focused on Biden’s close friendship with her late husband.

A Navy pilot, John McCain was shot down over North Vietnam in 1967. He was captured, beaten and held prisoner for more than five years, refusing to be released ahead of other American servicemembers.

During his 2016 campaign, Trump said of McCain, “He’s not a war hero. He was a war hero because he was captured. I like people who weren’t captured.”

Biden, who served in the Senate for decades overlapped with Sen. John McCain.