Arizona Senator John McCain's brain cancer diagnosis is shaking the nation's capital. On Twitter, former President Obama called McCain an American hero and one of the bravest fighters he's ever know. Obama, who faced McCain in the 2008 presidential race, added "cancer doesn't know what it's up against. Give it hell, John." McCain's fellow Arizona Senator Jeff Flake wrote on Twitter "tough diagnosis, but even tougher man." In a statement, Senate Majority Leader Mitch McConnell said McCain has never shied away from a fight and will face the disease with the same "extraordinary courage that has characterized his life."
Hillary Clinton said on Twitter that McCain is "as tough as they come" and that she's thinking of the senator and his family. McCain's running mate in the 2008 presidential race Sarah Palin said she knows he'll face his cancer diagnosis with courage and strength.