Joe Biden Joe BidenBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Democratic groups using Bloomberg money to launch M in Spanish language ads in Florida Harris faces pivotal moment with Supreme Court battle MORE's presidential campaign praised "strong progressive voices" for standing up against Rudy Giuliani Rudy GiulianiThe Hill's Campaign Report: GOP set to ask SCOTUS to limit mail-in voting CIA found Putin 'probably directing' campaign against Biden: report Democrats fear Russia interference could spoil bid to retake Senate MORE after President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE's personal attorney said he would travel to Ukraine to press for an investigation into the former vice president.

"It's great to see all these strong progressive voices stand up to this attempt at a blatantly political smear which in and of itself reflects the urgent need for change and to restore the soul of the country," a Biden campaign official told CNN.

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Giuliani first revealed his plans to travel to Ukraine in an interview with The New York Times last Thursday.

The president's lawyer said he hoped to ask the country's president-elect to pursue inquiries that could yield new information about the origin of special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's Russia investigation and Biden's past influence in Ukraine.

Giuliani last week called for an investigation into Biden after the Times reported that Biden allegedly threatened to withhold $1 billion in U.S. loan guarantees in 2016 unless Ukraine removed a top prosecutor, who was later voted out.

Giuliani changed course and cancelled the visit on Friday, blaming Democrats for trying to "spin" the trip.

Several Democrats, including 2020 candidates, had expressed concerns about Giuliani's planned trip.

"I just think it is highly unethical for the President's personal lawyer to go meet with officials from foreign government to see if they can influence somehow the upcoming presidential election," Sen. Elizabeth Warren Elizabeth WarrenDimon: Wealth tax 'almost impossible to do' CNN's Don Lemon: 'Blow up the entire system' remark taken out of context Democrats shoot down talk of expanding Supreme Court MORE (D-Mass.) said at a campaign stop in West Virginia, according to CNN. "We've had enough of that and Rudy Giuliani should just back off."

Former Rep. Beto O'Rourke Beto O'RourkeJimmy Carter says his son smoked pot with Willie Nelson on White House roof O'Rourke endorses Kennedy for Senate: 'A champion for the values we're most proud of' 2020 Democrats do convention Zoom call MORE (D-Texas) said Giuliani's proposed trip to Ukraine was "so very troubling, very disappointing, and yet not a total surprise, given this president's behavior and the pattern that he'd already set," while in New Hampshire.

House Judiciary Committee Chairman Jerrold Nadler Jerrold (Jerry) Lewis NadlerDemocrats shoot down talk of expanding Supreme Court Schumer: 'Nothing is off the table' if GOP moves forward with Ginsburg replacement Top Democrats call for DOJ watchdog to probe Barr over possible 2020 election influence MORE (D-N.Y.) also slammed the move, saying, "We've come to a very sorry state when it's considered OK for an American politician, never mind an attorney for the president, to go and seek foreign intervention in American politics."

In a tweet, House Intelligence Committee Chairman Adam Schiff Adam Bennett SchiffPelosi, Democrats unveil bills to rein in alleged White House abuses of power Chris Matthews ripped for complimenting Trump's 'true presidential behavior' on Ginsburg Trump casts doubt on Ginsburg statement, wonders if it was written by Schiff, Pelosi or Schumer MORE (D-Calif.) called the plan "immoral, unethical, unpatriotic and, now, standard procedure."