President Donald Trump and Sen. Bob Corker escalate their Twitter feud

— -- President Donald Trump and Sen. Bob Corker are back at it, trading barbs over Twitter.

Corker, R-Tenn., appeared this morning on several news shows, questioning Trump's capabilities in dealing with North Korea and standing by his earlier claims that Trump has turned the White House into an “adult day care center.” Trump then returned the favor, attacking Corker as a "lightweight" and saying that Corker is "fighting Tax Cuts."

The back-and-forth between the president and the Republican chair of the Senate Foreign Relations Committee is not new.

Earlier this month, Corker angrily responded to Trump’s assertion that he decided not to run for another term after Trump refused to endorse him.

Their relationship wasn't always this tense. Trump praised Corker during the presidential campaign, saying that he was "somebody respected by everybody" and "a fantastic guy."

Here's the Twitter back-and-forth between Trump and Corker.