“@KamalaHarris started strong in the Democrat Primaries, and finished weak, ultimately fleeing the race with almost zero support,” Trump tweeted Wednesday morning. “That’s the kind of opponent everyone dreams of!”
But that criticism was relatively muted and at his White House news conference Tuesday, Trump reverted to his familiar line of attack on powerful women, calling her "nasty," just as he notably did with his 2016 presidential opponent, former Secretary of State Hilary Clinton, and what he's said as well about House Speaker Nancy Pelosi and late former first lady Barbra Bush.
“She was nasty to a level that was just a horrible thing,” Trump said. “She was the meanest, most horrible, most disrespectful of anybody in the U.S. Senate,” referring to her treatment of his Supreme Court nominee Brett Kavanaugh.
On the policy front, while Trump has repeatedly hammered Biden as weak on crime, and has falsely claimed that he wants to "defund the police," that line of attack is now more complicated because Harris is a former attorney general who has a tough-on-crime reputation as a prosecutor.
GOP struggles to label Harris
Usually, Trump can come up with original, yet insensitive or offensive, nicknames for his political foes, calling Biden “Sleepy Joe” and Sen. Elizabeth Warren “Pocahontas,” for example.
But he seems to have struggled coming up with one he thinks he can stick on Harris, beyond calling her "phony."
In that same press conference and in a Fox News interview that same evening, Trump attempted to labeled Harris as “the most liberal person” in the Senate.
That would be news to her progressive Senate colleagues Elizabeth Warren and Bernie Sanders -- who is a self-proclaimed Democratic socialist.
Even as Trump attacked Harris as a liberal, campaign aide Brad Parscale said Harris would be rejected by liberals.
Republican National Committee Chairwoman Ronna McDaniel echoed Trump’s sentiments saying in a statement, “Kamala Harris’ extreme positions … show that the left-wing mob is controlling Biden’s candidacy, just like they would control him as president.”
However, later that evening the RNC argued a very different point, saying “Liberals revolt against Biden, Harris ticket” in a news release.
Vice President Mike Pence Tuesday came out swinging at Harris during an event in Arizona characterizing her to supporters as representing the “radical left” with promises of “socialized medicine and abortion on demand.”
“As you all know, Joe Biden and the Democratic Party have been overtaken by the radical left," Pence said. "So given their promises of higher taxes, open borders, socialized medicine and abortion on demand, it’s no surprise that he chose Sen. Harris."
He added, "So my message to the Democratic nominee for vice president: Congratulations. I’ll see you in Salt Lake City,” site of their October debate.
Trump’s past donations and compliments
As Trump’s attacks on Harris are just ramping up, as a private citizen the president donated thousands of dollars to her campaign twice when she was a candidate for California attorney general.
After 2010, almost all of Donald Trump's political donations were going to Republicans -- but he was still giving money to Harris.
Trump campaign senior adviser Katrina Pierson Tuesday said that Trump donating to Harris proves he is not a racist.
"I'll note that Kamala Harris is a black woman and he donated to her campaign so I hope we can squash this racism argument," Pierson said on a campaign call with reporters.
A spokesperson for Harris told ABC News that this money was donated to charity in 2015.
While the president is not financially supporting Harris’ bid against him this fall, Trump did have positive things to say about her candidacy for president earlier this year.
When asked by the New York Times in February whether there was anyone in the immense 2020 Democratic field who he thought might be his toughest opponent he cited Harris.
"I would say, the best opening so far would be Kamala Harris," Trump responded. "I would say, in terms of the opening act, I would say, would be her."
ABC News' Terrance Smith, Benjamin Siegel, Will Steakin and Zohreen Shah contributed to this report