But the longtime Republican "maverick" of the US Senate was lauded over the weekend in the Boston area for his willingness to compromise and work for the greater good of the country.
War hero, presidential contender and Arizona Senator, John McCain, has died today at the age of 81.
Klobuchar says McCain was a mentor to so many Senators, and he taught them all how to work with leaders on the world stage.
Mr. Obama, who defeated McCain in 2008 presidential race, issued a statement shortly after McCain's death saying that "we shared, for all our differences, a fidelity to something higher - the ideals for which generations of Americans and immigrants alike have fought, marched, and sacrificed".
"A passionate advocate for American global leadership, Senator McCain rightly bemoaned those who favored a United States pullback from world affairs", Harris added.
"My heart is broken", she wrote.
"It was his lifeblood and our nation was the beneficiary of his strength".
A statement from Ducey's office said that "now is a time for remembering and honoring a consequential life".More news: Lionel Messi wants Barcelona to sign Marcos Alonso
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According to the Post, Trump has maintained his stance that McCain is not a war hero since he first made the controversial comments about liking war veterans who "weren't captured" in 2015. While McCain has been treated for cancer in Arizona and unable to vote in Washington, his party's already narrow Senate majority had shrunk from two votes to one.
Just hours before the death of US Senator John McCain, a onetime political rival suggested that his decision to end cancer treatment could have been a political move created to hurt her campaign. Kennedy died on August 25, 2009.
Meanwhile, President Trump issued a two line tweet expressing his sympathies to the McCain family.
"In an era filled with cynicism about national unity and public service, John McCain's life shone as a bright example".
"John was up next and, seamlessly, it seemed, took Ted's notes and completed the questioning. We will all miss the great man that he was".
Sen. John McCain's former Vietnamese jailer said he respected his former inmate and felt sad about his death, as others in Vietnam paid their respects to the former U.S. Navy pilot who was a prisoner of war and later was instrumental in bringing the wartime foes together.
Former President Jimmy Carter called McCain "a man of honor, a true patriot in the best sense of the word".
After Trump's joint press conference with Russian President Vladimir Putin in July, in which Trump did not endorse USA intelligence findings on Russian election meddling over Putin's denial, McCain said: "The damage inflicted by President Trump's naivete, egotism, false equivalence, and sympathy for autocrats is hard to calculate".
Joe Cloonan, 65, of Reading, who was visiting the institute with his daughter, praised McCain for his military service and congressional career.
On the Sunday morning news shows, remembrances of McCain poured in from both sides of the political aisle.