Cindy McCain, the widow of Senator John McCain, endorsed Joe Biden, saying,
"My husband John lived by a code: country first. We are Republicans, yes, but Americans foremost. There's only one candidate in this race that 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. And, 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.
"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."
During the Democratic National Convention, McCain lent her voice to a video highlighting Senator McCain and Joe Biden's friendship and bipartisan work.
Mrs. McCain joins a long list of Republicans who have endorsed Joe Biden, including former Senator Jeff Flake and more than two dozen former Republican Members of Congress.
Joseph R. Biden, Jr., Biden Campaign Press Release - Cindy McCain Endorses Joe Biden for President Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/345284