Joe Walsh becomes second Republican to challenge Trump for White House

Joe Walsh, a conservative former U.S. congressman turned talk show host, on Sunday became the second Republican to challenge President Donald Trump for the party's 2020 White House nomination.

Walsh, 57, announced his long-shot bid to unseat Trump, who has strong support among Republicans, after sharply criticizing the Republican president as a liar and a bully who is unfit for office.

"I'm running because he's unfit," Walsh told ABC's "This Week" program. "Somebody needs to step up."