CNN  — 

Whatever issues Democratic Sens. Joe Manchin and Kyrsten Sinema have caused for President Joe Biden’s legislative agenda, their records on Biden’s judicial confirmation efforts are a positive signal for the President as he seeks to replace the retiring Justice Stephen Breyer.

Neither Manchin nor Sinema has voted against any of Biden’s lower court nominees so far – including Biden’s picks for the federal judiciary who have attracted significant Republican heat.

Manchin and Sinema stuck with the rest of the Democratic caucus when Republicans were united against the confirmation of Jennifer Sung to the 9th US Circuit Court of Appeals – a confirmation that required the tie-breaking vote of Vice President Kamala Harris to move forward.

Manchin in particular has attracted liberal ire for holding up Biden’s Build Back Better spending plan, and both the West Virginia Democrat and Sinema voted against Democrats’ efforts to end the use of the 60-vote filibuster on voting rights legislation. But the filibuster isn’t in play for Supreme Court votes anymore.

Since Senate GOP leader Mitch McConnell pushed through a change in filibuster rules in 2017 to confirm Neil Gorsuch, it just requires a party-line, simple majority vote to advance a Supreme Court nominee.

In the 50-50 Senate, all Democrats need to do is stay united, with Harris breaking a potential tie in the event no Republicans break ranks.

Voted for judges already on Biden’s shortlist

Manchin and Sinema have already voted in favor of several of the federal judges, when they were up for lower court vacancies, who are now said to be in contention for Breyer’s seat. Biden has vowed to select a Black woman for the role, which would be a historic first for the high court.

Breyer replacement front-runner Judge Ketanji Brown Jackson had the support of both Manchin and Sinema when she was elevated to the US DC Circuit Court of Appeals, a familiar launchpad for future Supreme Court justices. Manchin was also in the Senate when Jackson was confirmed to DC’s district court by voice vote in 2013.

Sinema and Manchin both backed fellow Supreme Court short-listers Judge Eunice Lee – when she was confirmed to the 2nd US Circuit Court of Appeals in August – and Judge Candace Rae Jackson-Akiwumi, who was approved for the 7th Circuit in June.

Manchin also supported Judge Wilhelmina “Mimi” Wright, another name being floated for replacing Breyer, when she was confirmed to the US district court in Minnesota in 2016. (Sinema was not in the Senate at that time.)

In a statement issued by Manchin after news of Breyer’s retirement broke Wednesday, the West Virginian said he takes “very seriously” his “Constitutional responsibility to advise and consent on a nominee to the Supreme Court.”

Sinema, who represents Arizona, has not yet spoken publicly about Breyer’s pending retirement. In the past, she has said that when she is weighing nominees for the federal judiciary, she considers whether the nominee is “professionally qualified, believes in the role of an independent judiciary, and can be trusted to faithfully interpret and uphold the rule of law.”

Senate Majority Leader Chuck Schumer plans to follow a timeline similar to the one that Republicans employed to confirm Amy Coney Barrett to the court in 2020, according to a source familiar with his thinking.

The late Justice Ruth Bader Ginsburg died on September 18, 2020 – and Barrett was nominated on September 26, 2020. She was confirmed October 26, 2020 – just days before the presidential election.

GOP support?

Based on past votes, it’s worth noting there could be some GOP support for a Biden nominee, although lower court judges don’t get the same level of attention as Supreme Court justices.

Jackson had the support of Republican Sens. Susan Collins of Maine, Lindsey Graham of South Carolina and Lisa Murkowski of Alaska when she was confirmed to the DC Circuit. The same trio of Republicans voted to put Judge Jackson-Akiwumi on the appeals court last year. Graham also praised J. Michelle Childs in 2010, another thought to be on Biden’s shortlist, when she was being considered for a US District Court judgeship in South Carolina, which the Senate confirmed her to by voice vote.

Graham, however, has indicated that things may all be about party this time.

“If all Democrats hang together – which I expect they will – they have the power to replace Justice Breyer in 2022 without one Republican vote in support,” Graham said in a statement Wednesday. “Elections have consequences, and that is most evident when it comes to fulfilling vacancies on the Supreme Court.”

CNN’s Lauren Fox and Manu Raju contributed to this report.