Cindy McCain previously expressed support for Biden during the Democratic National Convention last month — appearing in a video focused on the former vice president’s “unlikely friendship” with her husband, the longtime Arizona senator and 2008 Republican presidential nominee.

But McCain made her endorsement official Tuesday, tweeting that there is “only one candidate” in the presidential race “who stands up for our values as a nation.”

“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,” McCain wrote. “He will lead us with dignity.”

McCain also argued Biden “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.”

McCain’s husband, a former Navy pilot, spent roughly five-and-half years in a notorious North Vietnamese prison where he was repeatedly tortured and spent two years in solitary confinement.

Throughout his first presidential campaign and tenure in office, Trump has repeatedly disparaged the late senator, memorably insisting in 2015 that “he’s not a war hero” and remarking: “I like people who weren’t captured.”

The president’s attacks only escalated after the late senator cast the deciding vote to tank Republican efforts to repeal the Affordable Care Act — the signature legislative achievement of McCain’s former general election rival.

Trump’s tweet Wednesday came as Cindy McCain appeared on several network morning news shows promoting her endorsement of Biden.

“I’ve been watching what’s going on, and I’m deeply concerned,” McCain told NBC’s “Today” show in an interview.

“I want to feel like my president cares about me and cares about this country. And Joe Biden does,” she said. “I’ve known Joe for over 40 years, and I know the kind of man that he is.”

McCain’s endorsement could carry significant weight with voters in Arizona, a swing state where the late senator remains a venerated figure.

Trump won Arizona’s 11 Electoral College votes by 4.1 percentage points in 2016, but he is now locked in a close contest there with Biden.

“I’m hoping that I can encourage suburban women to take another look,” at Biden’s campaign, McCain said — especially those who “are on the fence and are unhappy with what’s going on right now, but also are not sure they want to cross the line and vote for Joe.”

Asked what her husband would think about her endorsement, McCain said the late senator “would have been disappointed in what’s going on” and “certainly upset about the direction the country’s going.”

“I hope — you know, if I look up — I hope he’s happy with what I’m doing and believes that I’ve done the right thing,” she said. “And so that’s all I can ask for.”

Prior to Cindy McCain’s endorsement announcement Tuesday, Biden said at a virtual fundraiser that the late senator’s wife had decided to formally back him after The Atlantic and other news outlets reported earlier this month that Trump made numerous derogatory comments about U.S. service members and America’s war dead.

Biden’s late son Beau, a former Delaware attorney general and Iraq War veteran, died in 2015 from the same aggressive form of brain cancer that resulted in Sen. McCain’s death in 2018.

Cindy McCain is not the first widow of a prominent American military veteran to come under fire from the president.

Last December, Trump criticized Rep. Debbie Dingell (D-Mich.) during a campaign rally in her home state, as the congresswoman voted to approve impeachment articles against the president charging him with abuse of power and obstruction of Congress.

Trump recounted to supporters how Dingell had called him last February following the death of her husband, former Rep. John Dingell — a World War II veteran and the longest-serving member of Congress.

The president claimed the congresswoman thanked him for the “A+ treatment” he provided by ordering all U.S. flags to fly at half-staff. Trump went on to suggest that Dingell’s late husband was in hell.

Debbie Dingell later sought to clean up the president’s version of events, contending it was actually Trump who called her to say he would be lowering the flags. She also clarified that her husband did not lie in state in the Capitol Rotunda after Trump appeared to imply he had arranged a memorial for him there.