WASHINGTON -- U.S. Sen. Cory Booker said it would be a "potential conflict of interest" for President Donald Trump to nominate anyone to the U.S. Supreme Court while members of his administration and presidential campaign remain under federal investigation over possible ties to Russia.

As a result, Booker, D-N.J., called on his Senate Judiciary Committee colleagues Thursday to delay action on any Trump nominee to succeed Justice Anthony Kennedy until after special counsel Robert Mueller's work is done.

"I think it's questionable we should be considering a nominee from a president who has a history of demanding these loyalty tests and we could be responsible for participating in something that could undermine that investigation," Booker said.

"I do not believe this committee should, or can in good conscience, consider a nominee put forward by this president until that investigation is concluded," he said.

Republican National Committee spokesman Michael Ahrens rejected Booker's assertion.

"There's no justification for Democrats to obstruct here, so they're desperately trying to set a new standard as a political play to their base," Ahrens said. "Democrats must consider a nominee without delay."

Booker is mentioned as a potential 2020 Democratic presidential candidate, and Sarah Dolan, a spokeswoman for the pro-Republican America Rising Political Action Committee, suggested that his position was "the start of the ridiculous obstructionist tactics" from those interested in taking on Trump in two years.

"In the ongoing race to the left, Senator Booker is going to desperate lengths to distinguish himself from the growing number of Democrats looking to run for president in 2020," Dolan said. "It's a reckless stunt that's completely divorced from political reality and a complete abdication of the senator's constitutional responsibilities."

Trump, meanwhile, said on Twitter Thursday that he believed the assertions of Russian President Vladimir Putin over the conclusions of U.S. intelligence agencies, which said there was no question that Moscow intervened in the American presidential election on behalf of the Republican candidate.

Russia continues to say they had nothing to do with Meddling in our Election! Where is the DNC Server, and why didn’t Shady James Comey and the now disgraced FBI agents take and closely examine it? Why isn’t Hillary/Russia being looked at? So many questions, so much corruption! — Donald J. Trump (@realDonaldTrump) June 28, 2018

Despite Trump's protests, Mueller's investigation is continuing.

"We've seen numerous people that are close to the president, numerous people that were on the president's campaign, who have plead guilty, who have been clearly been under investigation," Booker said.

"This all could end up in front of the Supreme Court. And we have a president who has in the past has seemed to be asking people for loyalty tests, that has seemed to have litmus tests in regard to this investigation," he said.

Also Thursday, all five House Republicans from New Jersey voted in favor of a resolution demanding that the Justice Department turn over documents related to the Russian investigation.

The measure, which passed along party lines, was championed by House GOP conservatives who have joined Trump in criticizing the independent investigation and accusing the FBI of bias because it did not recommend charging Hillary Clinton for her use of a private email server.

If Rod Rosenstein and the Department of Justice have nothing to hide, they certainly haven't acted like it.



Turn over the documents, Mr. Rosenstein. Show Congress and the American people the truth. pic.twitter.com/TXe6o6yQZp — Mark Meadows (@RepMarkMeadows) June 28, 2018

While a recent report by Justice Department Inspector General Michael Horowitz criticized the FBI's actions in the Clinton probe, it found no problems with the decision not to prosecute.

"We found no evidence that the conclusions by the prosecutors were affected by bias or other improper considerations; rather, we determined that they were based on the prosecutors' assessment of the facts, the law, and past department practice," the report said.

Trump has claimed he has the right to pardon himself, and House Judiciary Committee Republicans rejected a resolution sponsored by Rep. Bill Pascrell Jr., D-9th Dist., to force the president to provide information about discussions on possible presidential pardons.

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant or on Facebook. Find NJ.com Politics on Facebook.