Sen. Bernie Sanders (I-Vt.) knocked President Donald Trump as he paid tribute to former President George H.W. Bush on Thursday’s broadcast of “The Late Show.”

Sanders told host Stephen Colbert that “yes, of course I disagreed” with Bush, who died last week at age 94. “But he was an honest man, he was a decent man, he loved his country very much and, you know, we wish that we could have president who is honest back in the White House again,” he added.

Sanders also updated Colbert on speculation he’ll mount a presidential challenge to Trump in 2020.

“The answer is, look, when you run for president of the United States, especially in this ugly political world that we live in right now, it is a very difficult decision for one’s family,” explained Sanders, who said he hasn’t decided whether he’ll go for it.

He said he was “trying to ascertain, quite honestly, going beyond ego” which candidates have the best chance to beat Trump and “can most turn this country around so that we have a government that works for all of us and not just the people on top.”

Check out the clip here: