A Vietnam POW and a known defense hawk, McCain lost his bid for the White House to Barack Obama in 2008.
The first female Secretary of State, Madeleine Albright also paid tribute: "I have not know anyone with greater courage, stronger convictions or more devotion to country than John McCain", she tweeted.
McCain was a two-time presidential candidate, losing the GOP nomination in 2000 to George W. Bush and the general election in 2008 to Barack Obama, when he ran alongside Palin. His family and friends will be in our prayers. "We saw this country as a place where anything is possible - and citizenship as out patriotic obligation to ensure it forever remains that way".
McCain tried to inject some youth and enthusiasm into his campaign with his selection of Palin, Alaska's governor, as his running mate.
Republicans, driven by Trump, were one vote away from advancing a repeal of Obama's health care law. "We're getting nothing done", he said.
He was the chairman of the Senate Armed Services Committee, was a frequent critic as well as a target of his fellow Republican, Trump, who was elected president in November 2016. "God bless John McCain". He said that "the nation mourns the loss of a great American patriot" and that the Senate is "keeping Cindy, the McCain family, all John's friends and staff, and the people of Arizona in our prayers at this tremendously hard time".
"On behalf of myself, Jill, and the entire Biden family, our sincerest condolences go out to Cindy, Doug, Andy, Sidney, Meghan, Jack, Jimmy, Bridget, and the entire McCain family". As a leader of the Armed Services and Foreign Relations committees, he was at the forefront of a group of senators who saw Putin's Russian Federation as a growing threat to America.
McCain ran twice for President.
The son and grandson of Navy admirals, McCain was taught the value of civic duty from an early age. He broke his leg and an arm in the crash.
Born in the Panama Canal Zone on August 29, 1936, McCain went on to follow in the footsteps of his Naval officer father and joined the Navy.
McCain entered the Naval Academy in 1954, soon after graduating from a prep school in Alexandria, VA. He was pulled out of the water by a Vietnamese mob and was stabbed, beaten and taken to a prison commonly referred to as the "Hanoi Hilton". Cortney wrote on Friday that Mr. McCain would be suspending medical treatment. His most recent bestseller and planned farewell, "The Restless Wave", came out in May 2018.
He spent most of his time in solitary confinement and endured incessant torture.
When Republicans took control of the Senate in 2015, McCain embraced his new influence as chairman of the Armed Services Committee, pushing for aggressive USA military intervention overseas and eager to contribute to "defeating the forces of radical Islam that want to destroy America".
He was released in January of 1973, nearly six years after his capture.
He retired in 1981 as a captain, after receiving numerous decorations including the Silver Star, two Bronze Star medals, two Purple Hearts and a Prisoner of War commendation. McCain was one of ten Senate Republicans to vote in favor of the Employment Non-Discrimination Act that would bar employers from discriminating based on sexual orientation or gender identity and was a vocal opponent of Arizona's proposed "license to discriminate" bill.