By MOLLY NAGLE, ABC News

(WASHINGTON) — Cindy McCain, the widow of Sen. John McCain, has crossed party lines to offer her endorsement of Joe Biden, the Democratic nominee for president.

“I, like everyone else, want to have a president that will have my back, that shows empathy and compassion, who has courage and dignity in how they lead and that’s Joe Biden,” McCain said on ABC’s Good Morning America Wednesday morning.

“I’ve known Joe for over 40 years, and my husband and I were good friends with them. And I just felt like it was time to take a stand on this,” she said.

McCain first offered her endorsement in a statement released Tuesday night.

“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,” Cindy McCain said.

“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,” she continued. “There is too much at risk in this election to sit on the sidelines. Everything this country stands for is on the line. I’ll be putting our country first and voting for Joe Biden, and I hope you will join me.”

News of Cindy McCain’s endorsement first came from Biden himself, who revealed during a virtual fundraiser Tuesday afternoon that he was speaking with her about her impending endorsement.

“Maybe I shouldn’t say it, but I’m about to go on one of these Zooms with John McCain’s wife, who… 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 [the president] said they’re losers, they’re suckers,” Biden said, alluding to a report by the Atlantic that President Donald Trump made disparaging remarks about service members.

ABC News has not independently confirmed The Atlantic report, which cites four unnamed sources with direct knowledge of the claims.

“You know, you can say a lot of things but men and women who gave the ultimate sacrifice are not losers, and people that serve are not losers,” McCain added Wednesday.

Prior to her official endorsement of Biden, Cindy McCain hinted at her support, lending her voice to a video highlighting Biden’s friendship with her late husband during the Democratic National Convention in August.

Trump responded to McCain’s endorsement in a tweet Wednesday morning, saying in part, “Never a fan of John. Cindy can have Sleepy Joe!”

Trump and the late senator had an adversarial relationship throughout the 2016 campaign and Trump’s presidency, with the president arguing that he did not view McCain, who was held as a prisoner of war for more than five years during the Vietnam War, a hero, because he was captured.

The Republican senator, in turn, withdrew his support for Trump during the 2016 election following the release of the Access Hollywood video that featured Trump making lewd comments about women. He also further angered the president by delivering a “thumbs down” vote to thwart efforts to repeal the Affordable Care Act in 2017.

Cindy McCain joins a growing list of Republicans who have offered their support to Biden — including former Arizona Sen. Jeff Flake, Former Ohio Gov. John Kasich, and former Pennsylvania Rep. Charlie Dent — and could help Biden win over disaffected Republicans in the 2020 election, which is just 41 days away.

Her endorsement also comes as Biden is looking to expand his electoral map to include Cindy McCain’s home state of Arizona, with recent state polling showing he and Trump are in a tight race in the state.

“I’m hoping that I can convince suburban women who are kind of on the fence about things to come with me on this and step out of their comfort zone and join Team Biden and, and vote a man in who would be not only a marvelous president, who shows the character the integrity, the values, and the wherewithal to be present,” McCain said on GMA.

Biden and John McCain shared a bipartisan friendship throughout their long political careers that included facing off against one another in the 2008 presidential election. Following McCain’s death in 2018 from Glioblastoma, Biden gave a tearful eulogy of his friend.

“My name is Joe Biden. I’m a Democrat. And I loved John McCain,” said Biden, who lost his son Beau in 2015 to the same disease that claimed John McCain’s life.

“I always thought of John as a brother,” he added. “We had a hell of a lot of family fights. We go back a long way.”

In a tweet Tuesday night, Biden thanked Cindy McCain for her support.

“Cindy — I’m deeply honored to have your support and your friendship. This election is bigger than any one political party. It requires all of us to come together as one America to restore the soul of the nation. Together, we’ll get it done,” he wrote.

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