“I say no chance,” the president said, when asked about Mr Booker’s likelihood of assuming the Oval Office while appearing on CBS’s Face the Nation.
Mr Trump didn’t offer much reasoning behind his prediction, but when pressured, said: “Because I know him. He has no chance.”
Mr Booker formally declared his presidential campaign on Friday morning and followed with a press conference outside his home in Newark, New Jersey.
In a interview with Politico, the 49-year-old senator emphasised that his presidential campaign would not focus on “who I’m against or what I’m against".
“I don’t know the heart of anybody,” Mr Booker, who was raised in a religious black Methodist household, said. “I’ll leave that to the lord.”
The president, however, doesn’t seem fazed by the Democratic challengers who have declared their candidacy.
“So far, I don’t see anybody,” Mr Trump said. "I’m not impressed with their group."
But Mr Trump added: “I would say, the best opening so far would be Kamala Harris," referring to the junior Senator from California’s 2020 White House bid. “I would say, in terms of the opening act, I would say, would be her.”
Mr Trump also doubled down on his goading of Senator Elizabeth Warren’s self-claimed Native American heritage. Last month, the president said he hoped to see the Massachusetts Democrat run in the 2020 election.
“We’ll see how she does, I wish her well,” Mr Trump said, before again calling her “Pocahontas". “I hope she does well. I’d love to run against her.”
“Howard Schultz doesn’t have the guts to run for President! Watched him on [60 Minutes] last night and I agree with him that he is not the ‘smartest person',” Mr Trump tweeted.
“Besides, America already has that! I only hope that Starbucks is still paying me their rent in Trump Tower!”
In addition to Mr Booker, Ms Harris and Ms Warren, the long – and still growing – list of Democratic presidential candidates include Hawaii rep. Tulsi Gabbard, former Maryland rep. John Delaney, and former secretary of Housing and Urban Development Julián Castro.
New York Senator Kirsten Gillibrand has also formed a presidential exploratory committee, but has not yet made an official announcement.
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