Sen. Rand PaulRandal (Rand) Howard PaulThese Senate seats are up for election in 2022 I'm furious about Democrats taking the blame — it's time to fight back Rand Paul cancels DirecTV subscription after it drops OAN MORE (Ky.) said on Monday that he will oppose President TrumpDonald TrumpJudge rules Alaska governor unlawfully fired lawyer who criticized Trump Giuliani led fake electors plot: CNN Giuliani associate sentenced to a year in prison in campaign finance case MORE's attorney general nominee, becoming the first Republican to come out as a "no" vote on William Barr.
Paul told Politico that he had concerns about Barr's record on privacy, calling him a "chief advocate for warrantless surveillance of U.S. citizens."
A spokesman for Paul didn't immediately respond to a request for comment. The libertarian-leaning GOP senator had previously raised concerns about Barr, who also served as attorney general to President George H.W. Bush.
His opposition comes as the full Senate could take up Barr's nomination as soon as this week following his approval by the Judiciary Committee last Thursday on a party-line vote.
Paul's "no" vote isn't enough to sink Barr on its own. Republicans hold a 53-47 majority, meaning that if Democrats could keep their whole caucus united they would still need to flip four Republican senators to stymie the confirmation.
Sen. Doug Jones (D-Ala.) became the first Democrat to say last week that he would support Barr.
Jones's and Paul's defections mean Democrats still need to flip four Republicans to stop the nomination. Other potential swing votes, including Sen. Joe ManchinJoe ManchinLawmaker arrested amid voting rights protest says he'd 'do it again' No Hillary — the 'Third Way' is the wrong way WATCH: The Hill recaps the top stories of the week MORE (D-W.Va.), have not announced how they will vote.
But Manchin told reporters earlier Monday that he viewed Barr "very favorably."