Vice President Kamala Harris said in a newly released video that former President Trump selected Sen. JD Vance, R-Ohio, as his running mate to be a "rubber stamp" for the Republican White House hopeful's "extreme agenda."

This comes ahead of Vance's acceptance speech on Wednesday at the Republican National Convention in Milwaukee. Trump, now formally the Republican nominee for president, announced Vance as his pick for vice president on Monday.

"Trump looked for someone he knew would be a rubber stamp for his extreme agenda," Harris said in the video.

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"Make no mistake: JD Vance will be loyal only to Trump, not to our country," she continued.

Harris and Vance spoke by phone after Vance's nomination in a brief and respectful conversation, Fox News' Alexis McAdams reports, after Harris left a congratulatory voicemail.

JD Vance, Kamala Harris

Vice President Kamala Harris said former President Trump chose Sen. JD Vance as his running mate to be a "rubber stamp" for his agenda. (Getty Images)

Harris also criticized Vance for saying in an interview with ABC News earlier this year that he would not have certified the 2020 election until states submitted pro-Trump electors if he were vice president at the time, noting in the interview that he believes unsubstantiated claims of election fraud in the 2020 election.

KAMALA HARRIS CONGRATULATES JD VANCE, HOPES 'THAT THE TWO CAN MEET' AT VP DEBATE

"Unlike Mike Pence, Vance said he would have carried out Trump's plan to overturn the 2020 election," Harris said.

The vice president further pointed to comments Vance made during his 2022 Senate campaign, when he said he supported a national abortion ban at 15 weeks, with some exceptions such as protecting the life of the mother. Harris also cited in her video Vance's vote last month against a Democrat-led bill to protect access to in vitro fertilization, or IVF. The bill was blocked by Republicans in the Senate.

"He supports a national abortion ban and voted against protecting IVF," Harris said of Vance.

kamala harris

Vice President Kamala Harris claimed Sen. JD Vance "will be loyal only to Trump" and not America. (Bizuayehu Tesfaye/Las Vegas Review-Journal/Tribune News Service via Getty Images)

Harris also referenced Project 2025, a controversial initiative organized by conservative think tank the Heritage Foundation and that was authored by a number of conservatives, including some former Trump administration officials.

Project 2025 offers right-wing policy recommendations for Trump should he win the presidency, including replacing civil service employees with Trump loyalists, abolishing the Department of Education, criminalizing pornography, eliminating DEI programs, cutting funding for Medicaid and Medicare, rejecting abortion as health care and infusing the government with Christian values.

TRUMP PICKS JD VANCE AS RUNNING MATE AS HE BECOMES GOP PRESIDENTIAL NOMINEE

JD Vance is introduced during the Republican National Convention

Former President Trump's pick for vice president, Sen. JD Vance, R-Ohio, is set to speak at the Republican National Convention on Wednesday night. (Anna Moneymaker/Getty Images)

Trump has sought to distance himself from the initiative, which has been criticized as an authoritarian and Christian nationalist plan that would undermine civil liberties, saying he knows nothing about it and that parts of it are "absolutely ridiculous and abysmal."

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"And if elected, [Vance] will help implement the extreme Project 2025 plan for a second Trump term, which would target critical programs like Head Start and Medicare," Harris said. "But we are not going to let that happen."