Former President Donald J. Trump on Wednesday blasted Vice President Kamala Harris as radically liberal and blamed her for what he called the Biden administration’s “disastrous” policies, repurposing attacks he had long leveled at President Biden now that Ms. Harris is poised to be his opponent in November.

Speaking in Charlotte, N.C., at his first campaign rally since President Biden dropped out of the race and Ms. Harris cleared the field of potential Democratic rivals, Mr. Trump called Ms. Harris “the ultraliberal driving force behind every single Biden catastrophe.”

Mr. Trump repeatedly mispronounced Ms. Harris’s name, called her a “radical-left lunatic” and tagged her with the nickname “Lyin’ Kamala.” He denounced her for casting a tiebreaking vote on legislation that he said had caused inflation and said she had embarrassed herself by trying and failing to deter Russia from invading Ukraine.

Mr. Trump and his campaign have been put on their heels by the sudden disruption this week of a presidential contest that had seemed set in place for months. In the days since Sunday, when Mr. Biden dropped out of the race and endorsed Ms. Harris, Republicans have unveiled several lines of attacks.

Mr. Trump’s strategy on Wednesday appeared largely to consist of re-aiming at Ms. Harris criticisms that he had deployed against Mr. Biden for months.

He said she was “much worse” than Mr. Biden, calling the sitting president a “fake liberal” while saying Ms. Harris was a “real” one. He accused her of taking part in a “cover-up” in response to concerns about Mr. Biden’s fitness for the presidency.

After repeatedly insulting Mr. Biden’s intelligence, calling him “stupid” and “low I.Q.,” Mr. Trump mocked Ms. Harris on Wednesday for having failed the California bar exam the first time she took it.

And after long insisting, without evidence, that Mr. Biden was the mastermind behind all four of the criminal cases against him, Mr. Trump said that those cases were “all headed up” by Ms. Harris, because she was a former prosecutor. Yet, at the same time, he insisted Ms. Harris was a “really bad” prosecutor, though that seemed to undercut his point.

Continuing his effort to drive a wedge between American Jews and the Democratic Party, Mr. Trump also accused Ms. Harris of being opposed to the Jewish people because she did not attend Wednesday’s address to Congress by Prime Minister Benjamin Netanyahu. Ms. Harris, whose husband is Jewish, is expected to meet with Mr. Netanyahu privately on Thursday.

Shawn McCreesh contributed reporting.