(CNN) Friday's news that Sen. John McCain was ending medical treatment for an aggressive brain cancer shook Capitol Hill, a place where McCain's legacy looms large, and the larger political world, where the senior senator from Arizona is seen as an integral voice on everything from America's defense posture to the future of immigration.

In recent months, even far away from Washington, McCain would weigh in on President Donald Trump's foreign policy abroad and the future of the Senate.

Republicans and Democrats alike tweeted support for McCain and his family Friday, a reflection of just how far McCain's influence reached and how his politics and style transcended party lines:

Senate Majority Leader Mitch McConnell

Very sad to hear this morning's update from the family of our dear friend @SenJohnMcCain. We are so fortunate to call him our friend and colleague. John, Cindy, and the entire McCain family are in our prayers at this incredibly difficult hour. — Leader McConnell (@SenateMajLdr) August 24, 2018

Senate Minority Leader Chuck Schumer

My thoughts and prayers are with Senator McCain and his family. https://t.co/cqHXdjJntj — Chuck Schumer (@SenSchumer) August 24, 2018