The senator repeatedly made clear that he saw Trump and his America First ideology as a departure from the values and traditions of global leadership that he saw epitomized in the United States.
Barack Obama, the democrat who beat McCain to the presidency, said despite their differences, they shared "a fidelity to something higher - the ideals for which generations of Americans and immigrants alike have fought, marched and sacrificed".
Former presidents George W. Bush and Barack Obama are expected to speak at his funeral on Saturday. "As Chairman and longtime member of the Armed Services Committee, Senator McCain consistently worked to ensure that Israel had the critical resources to defend herself. I like people who weren't captured".
The two men had been at odds since Trump launched his presidential campaign in 2015, with McCain repeatedly attacking Trump and his policies.
Legendary CBS News anchor Dan Rather paid tribute to John McCain Monday on "Morning Joe", saying that his reputation as a "popular everyman hero" was forged from his service in Vietnam.
Sen. Bernie Sanders, I-Vt., also remembered McCain as "a man of decency and honor" and "a friend of mine". "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", the Kentucky Republican said in a statement.
The Washington Post reported Sunday that Trump went against the advice of senior aides to issue an official White House statement praising McCain for his heroism and decades of service, telling aides he instead wanted to post a brief tweet.
Critics on Saturday blasted for president for the seemingly superficial nature of his words for McCain.
For context, recall that Trump said McCain was not a war hero, mocked him for being a POW, and Trump's supporters and even staff have continued to mock the late Senator during his illness.
Later on in the day, McCain's casket will be flown to Washington D.C. from Phoenix.
Governor Doug Ducey, R-Arizona, does not plan to announce his selection of a Senate successor to McCain until after McCain's burial.