Story highlights Bob Corker is the powerful chairman of the Senate foreign relations committee

He offered the sharpest criticism of Trump of any Republican senator to date

(CNN) He called the White House "an adult day care center." He suggested President Donald Trump was setting the nation on a course to "World War III." And he said Trump "concerns me," adding that the President was treating the office "like a reality show."

And on Monday, Sen. Bob Corker stood by those remarks, adding: "My thoughts were well thought out."

"Look, I didn't just blurt them out," Corker, a Tennessee Republican, told CNN. "My comments -- my comments, I stand by them -- yes."

Corker also added a fresh complication to the intensifying White House push to overhaul the tax code, saying that he would oppose any tax-cut bill that would raise the deficit.

"No," Corker said when asked if he would back a tax plan that would hike the deficit. "I mean, I've stated that clearly."

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