CNN: The three Republicans challenging President Trump for the party's 2020 presidential nomination — Bill Weld, Joe Walsh and Mark Sanford — respond to Trump's tweet that "Never Trumper Republicans" are "human scum."

The three Republicans challenging President Trump for the party's 2020 presidential nomination — Bill Weld, Joe Walsh and Mark Sanford — responded to a Trump tweet this week where he said that "Never Trumper Republicans" are "human scum."

Bill Weld, the former Republican governor of Massachusetts, said "I return the favor" and called Trump a "reckless man" who is "endangering our Constitutional scheme."

Weld said that he supports removing Trump from office.

"Get rid of him, we must," Weld said.

Walsh, a former Illinois Republican congressman, called Trump a "traitor" and a "coward."

"He said 'human scum' yesterday, it'll be worse tomorrow," Walsh said. "He's going to get uglier."

On Trump's tweet, Sanford, a former South Carolina Republican governor and congressman, said it's "important we not respond" and added it's "important that we not dance his dance."