Sen. John McCain has passed away Saturday afternoon at the age of 81 after a battle with brain cancer.

The veteran senator from Arizona served in the Senate for nearly four decades and gained a reputation as a maverick for working across party lines and voting his conscious.

Last July, McCain was diagnosed with brain cancer around the time Congress was voting on repealing the Affordable Care Act, the Obama administration's benchmark legislation. He would return after treatment and cast the deciding vote to prevent millions from losing health care, according to the Los Angles Times.

McCain survived five and a half years as a prisoner of war in Vietnam. He ran for president in 2008 against then young and inspiring Sen. Barack Obama. He lost the election, but he remained an ally to the administration as a senator.

This last year was one of conflict for him. President Donald Trump would often trade barbs with the ailing elder statesmen for his defiant repudiation of the Trump administration, reports the BBC. A New York Times interview from earlier in the year revealed McCain had asked former Presidents George W. Bush and Barack Obama to eulogize him at his funeral. Trump, however, isn't welcomed.

"His intimates have informed the White House that their current plan for his funeral is for Vice President Mike Pence to attend the service to be held in Washington’s National Cathedral," The New York Times article reads. "… But not President Trump, with whom Mr. McCain has had a rocky relationship."

After his passing, major Democratic leaders such as Rep. John Lewis, Rep. Maxine Waters and others praised McCain as a Navy veteran, war hero and American political staple.

Our statement on the passing of Senator John McCain: pic.twitter.com/3GBjNYxoj5

— Barack Obama (@BarackObama) August 26, 2018

Hero. pic.twitter.com/fyqEB1czRW

— Eric Holder (@EricHolder) August 26, 2018

Senator John McCain was a warrior for peace. He will be deeply missed by people all around the world.

— John Lewis (@repjohnlewis) August 26, 2018

A true American patriot & hero has passed.
John McCain was an example of a public policy maker who fought for what he believed in, and had the character & dignity to stand up for what was right — even if he had to oppose some of his colleagues to do so.

— Maxine Waters (@RepMaxineWaters) August 26, 2018

My colleague John McCain will be remembered as a devoted father and husband, war hero and a conscience of the Senate. Sending my condolences and prayers to his friends and family, and to the American people who have lost a true patriot.

— Kamala Harris (@KamalaHarris) August 26, 2018

John McCain so warmly welcomed me to the Senate in ‘13. Our later private meeting in his office remains 1 of my most inspiring moments as a Senator.

Death may end a life but it can never end a love. John Loved America: his impact will forever endure. RIP https://t.co/c340f06GzB

— Cory Booker (@CoryBooker) August 26, 2018

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Sen. John McCain

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