Republican National Committee spokeswoman Kayleigh McEnany said Tuesday that 2020 Democratic hopefuls are resorting to attacks on President Trump because they "don't have the facts on their side."

Sen. Elizabeth Warren (Mass.) suggested in a recent campaign speech that Trump "may not even be a free person" in by the next election, and Sen. Amy Klobuchar (Minn.) responded to a joke from the president about her campaign announcement by quipping about his hair.

McEnany said on Outnumbered Overtime that the strategy of attacking Trump will prove to be ineffective come 2020.

"[Democrats] can't attack the economy ... the Russia collusion narrative just died ... all they have left is 'attack the president.' It will not work," she said.

Sen. Richard Burr (R-N.C.), chairman of the Senate Intelligence Committee, said in an interview last week that no evidence has been found "that would suggest there was collusion by the Trump campaign and Russia."

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Former Democratic National Committee Chair candidate Jehmu Greene argued that Trump can't keep the names of Democrats out of his mouth, and that it's a sign of fear.

"He's constantly tweeting about them. He's constantly trying to attach a nickname to them, and certainly they have every single right to be addressing this president head-on," Greene said, adding that Democrats have "a lot of juice" to attack Trump with regarding economic issues.

McEnany responded by saying that Trump is winning on a variety of issues, and that Democrats cannot "argue with the facts.:

"The Democrats don't have the facts on their side, so they don't bring up the economy, they bring up these hoax conspiracy theories ... but it's not going to work," she said.

Watch the debate from Outnumbered Overtime above.

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