McCain, a U.S. senator from Arizona for over three decades, had been battling glioblastoma, an aggressive brain cancer, discovered by his doctors in July 2017, and had not been at the U.S. Capitol in 2018.
He also had surgery for an intestinal infection in April of this year. His family had announced on Friday that McCain was discontinuing further cancer treatment.
A statement from his office on Saturday said: “Senator John Sidney McCain III died at 4:28 p.m. on August 25, 2018.
With the senator when he passed were his wife Cindy and their family. At his death, he had served the United States of America faithfully for sixty years.”
No further details were immediately provided.
“My heart is broken. I am so lucky to have lived the adventure of loving this incredible man for 38 years,” Cindy McCain wrote on Twitter. “He passed the way he lived, on his own terms, surrounded by the people he loved, in the place he loved best.”
Dr Ronda Zelezny-Green, a member of Democrats Abroad UK and Chair of the Media and Communications Committee for the Women's Caucus told Euronews, "McCain was one of the few Republicans known for his willingness to cross the aisle and achieve political compromises with Democrats. Although he did not do this frequently, it was more times than many Republicans cared to see occur."
"To me, his most memorable moment occurred recently when he gave the famous "thumbs down" on the vote to repeal Obamacare".
She added, "while his reasons for doing so were not at all aligned with that of Democrats', the dramatic vote was a fine demonstration of his willingness to stand up against pressure from his own party to do what he thought was right. I believe that he inspired many Americans because of his long service in the military and politics, and his continuous fight for veterans. Senator McCain, all Americans salute you!"
The vacancy created by McCain’s death narrowed the Republican majority in the U.S. Senate to 50 seats in the 100-member upper chamber, with Democrats controlling 49 seats.
But Republican Arizona Governor Doug Ducey is expected to appoint a member of his own party to succeed McCain.
That could also give Republicans a slight edge in the battle to confirm Brett Kavanaugh to the U.S. Supreme Court in the weeks ahead, as McCain had been too ill to cast any votes this year.
McCain had been in the public eye since the 1960s when as a naval aviator he was shot down during the Vietnam War and tortured by his North Vietnamese communist captors during 5-1/2 years as a prisoner.
He was edged out by George W. Bush for the Republican presidential nomination in 2000 but became his party’s White House candidate eight years later.
After gambling on Sarah Palin as his vice presidential running mate, McCain lost in 2008 to Democrat Barack Obama, who became the first black U.S. president.
Paying tribute to his onetime election opponent, Obama said in a statement that he and McCain, despite their “completely different backgrounds,” and political differences, shared “a fidelity to something higher - the ideals for which generations of Americans and immigrants alike have fought, marched and sacrificed.”
“We saw our political battles, even, as a privilege, something noble, an opportunity to serve as stewards of those high ideals at home, and to advance them around the world,” Obama wrote.
McCain, chairman of the Senate Armed Services Committee, remained prominent during and after the last White House race as both a frequent critic and target of his fellow Republican, Trump, who was elected president in November 2016.
McCain denounced Trump for among other things his praise of Russian President Vladimir Putin and other leaders the senator described as foreign “tyrants.”
“Flattery secures his friendship, criticism his enmity,” McCain said of Trump in his memoir, “The Restless Wave,” which was released in May.
McCain in July had castigated Trump for his summit with Putin, issuing a statement that called their joint news conference in Helsinki “one of the most disgraceful performances by an American president in memory.”
He said Trump was “not only unable but unwilling to stand up to Putin.”
Sources close to McCain have said Trump would not be invited to the funeral.
Shortly after McCain’s death was announced, Trump tweeted: My deepest sympathies and respect go out to the family of Senator John McCain.”
McCain, a foreign policy hawk with a traditional Republican view of world affairs, was admired in both parties for championing civility and compromise during an era of acrid partisanship in U.S. politics. But he also had a famous temper and rarely shied away from a fight. He had several with Trump.
He was the central figure in one of the most dramatic moments in Congress of Trump’s presidency when he returned to Washington shortly after his brain cancer diagnosis for a middle-of-the-night Senate vote in July 2017.
Still bearing a black eye and scar from surgery, McCain gave a thumbs-down signal in a vote to scuttle a Trump-backed bill that would have repealed the Obamacare healthcare law and increased the number of Americans without health insurance by millions.
Trump was furious about McCain’s vote and frequently referred to it at rallies, but without mentioning McCain by name.
McCain condemned his hard-line rhetoric on illegal immigration, after Trump in 2015 launched his presidential campaign, and said Trump had “fired up the crazies.”
Trump retorted that McCain was “not a war hero,” adding: “I like people who weren’t captured.”
After Trump became president, McCain blasted what he called the president’s attempts to undermine the free press and rule of law, and lamented the “half-baked, spurious nationalism” of the Trump era.
McCain denounced Trump’s performance at a summit meeting with Putin in July as “a tragic mistake,” adding, “The damage inflicted by President Trump’s naivete, egotism, false equivalence, and sympathy for autocrats is difficult to calculate.”
McCain, the son, and grandson of U.S. Navy admirals was elected to the U.S. House of Representatives from Arizona in 1982 after more than two decades of Navy service.
He served four years in the House before Arizona voters elected him to the Senate in 1986 to replace Barry Goldwater, the 1964 Republican presidential nominee revered by conservatives.
In running for president in 2008, McCain tried to succeed an unpopular fellow Republican in Bush, who was leaving office with the country mired in wars in Afghanistan and Iraq and stuck in a financial crisis.
It was a stark contrast between McCain, then a 72-year-old veteran of the Washington establishment, and the 47-year-old Obama, who was offering a “Yes, we can” message of change.
In his new book, McCain voiced regret for not choosing then-Senator Joe Lieberman, a Democrat turned independent, as his running mate.
McCain wrote that he had originally settled on Lieberman, Democrat Al Gore’s running mate in the 2000 election, but was warned by Republican leaders that Lieberman’s views on social issues, including support for abortion rights, would “fatally divide” the party.
“It was sound advice that I could reason for myself,” McCain wrote. “But my gut told me to ignore it and I wish I had.”