In a move that could give fence-sitting senators from both parties "political cover" in a full Senate vote to confirm U.S. Supreme Court nominee Brett Kavanaugh, Sen. Jeff Flake (R-Ariz.) called for a one-week delay so that the FBI can probe sexual assault allegations against Kavanaugh, even as he voted with 10 other Republicans on the Judiciary Committee on Friday to advance the nomination to the full chamber.

"If the FBI finds nothing new (as is likely), Collins, Murkowski, and Manchin are unquestionably more likely to vote yes."

—Lachlan Markay, Daily Beast

While Flake's threat to oppose Kavanaugh unless Republican leaders allow an investigation comes after Democratic lawmakers and protesters across the nation have spent days demanding such a probe, observers are warning that Flake and others may use it to eventually vote in favor of President Donald Trump's nominee.

After Flake, during a committee meeting on Friday, called for federal investigators to look into "current allegations"—Dr. Christine Blasey Ford, Deborah Ramirez, and Julie Swetnick have publicly accused Kavanaugh of sexual assault—Splinter News senior writer Hamilton Nolan tweeted:

Any "limited" FBI investigation will 100% be used as political cover for Flake and Collins et al to vote yes. — Hamilton Nolan (@hamiltonnolan) September 28, 2018

Flake is considered a key swing vote if and when Kavanaugh's nomination is brought to the Senate floor—along with Republican Sens. Lisa Murkowski (Alaska) and Susan Collins (Maine) as well as Democratic Sens. Joe Manchin (W.Va.) and Heidi Heitkamp (N.D.).

Murkowski told CNN on Friday that as long a probe is "limited in time and scope," she also supports "the FBI having an opportunity to bring some closure to this." Manchin and Collins released separate statements declaring their support for a one-week FBI investigation.

Daily Beast reporter Lachlan Markay posited on Twitter that if federal investigators don't uncover any new information about the alleged assaults that hasn't already been revealed in Thursday's hearing—which featured testimony from Ford—or media reports, "Collins, Murkowski, and Manchin are unquestionably more likely to vote yes."

I think pro-Kavanaugh folks dumping on Flake are seriously underestimating how savvy a move that was. He basically neutered Ds' central talking point. If the FBI finds nothing new (as is likely), Collins, Murkowski, and Manchin are unquestionably more likely to vote yes. — Lachlan Markay (@lachlan) September 28, 2018

Trump is required to sign off on the FBI reopening its background investigation into Kavanaugh. Asked about his willingness to do so by reporters at the White House on Friday, the president said that he "will be totally reliant on what" Judiciary Chairman Chuck Grassley (R-Iowa) "and the group decides to do."

The Senate Judiciary Committee, in a short statement on Friday, confirmed that it "will request that the administration instruct the FBI to conduct a supplemental FBI background investigation" that "would be limited to current credible allegations against the nominee and must be completed no later than one week from today," or Oct. 5.

"Yes, of course there should be an FBI investigation. But whatever they find doesn't change the fact that Kavanaugh, especially after his performance yesterday, is the most dangerous Supreme Court pick of our lifetime."

—Sen. Chris Murphy

When the committee's ranking member, Sen. Dianne Feinstein (D-Calif.), asked Kavanaugh during Thursday's hearing why he wasn't demanding an FBI probe himself, he said, "I'll do whatever the committee wants."

The Senate's second-ranking Republican, John Cornyn of Texas, told Bloomberg on Friday that while party leaders have agreed to a one-week delay to allow for an investigation, they still plan to hold a procedural vote on Saturday, as previously planned.

While some Senate Democrats expressed support for the investigation, they also noted that Kavanaugh's record as a federal judge had raised widespread alarm even before multiple sexual assault allegations surfaced.

"Yes, of course there should be an FBI investigation," Sen. Chris Murphy (D-Conn.) tweeted Friday. "But whatever they find doesn't change the fact that Kavanaugh, especially after his performance yesterday, is the most dangerous Supreme Court pick of our lifetime."