Democratic senator Bob Casey announced Monday morning he would be opposing President Trump's nominee to the U.S. Supreme Court, even though the president's choice for the nomination wouldn't be revealed for several more hours.

Casey is one of the handful of so-called "Red State" Democratic senators who are running for reelection in a state carried by the president in the 2016 election, and who are seen as especially vulnerable this election cycle as a result.

"I will oppose the nomination the President will make tonight because it represents a corrupt bargain with the far Right, big corporations, and Washington special interests," Casey said in a statement on his website.

The National Republican Senate Committee issued a quick criticism of Casey's announcement.

"Bob Casey's opposition to President Trump's nominee before he or she has even been named shows he has given up any pretense of being a moderate voice," said NRSC Spokesman Bob Salera in an emailed release. "Casey's willingness to oppose any nominee off of a list that includes judges he has previously voted for shows he will oppose President Trump at all costs, even when doing so makes him look like a partisan hack."

The recent Supreme Court vacancy created in late June when Associate Justice Anthony Kennedy announced his retirement has reshaped the 2018 midterms, with outlets like the New York Times popping out headlines like, "‘It's a Terrible Vote': Red-State Democrats Face an Agonizing Supreme Court Choice."

"Democratic senators running for re-election in Trump Country face an agonizing choice over President Trump's coming Supreme Court nominee: Vote to confirm the pick and risk demoralizing Democratic voters ahead of the midterm elections, or stick with the party and possibly sacrifice their own seats — and any chance at a Democratic majority in 2019," the Times reported.

The choice could be made all the more difficult for Casey if Trump nominates Thomas Hardiman, currently serving as a judge on the 3rd Circuit Court of Appeals which covers part of Pennsylvania, and who was first appointed to serve in U.S. District Court in Pittsburgh in 2003.

His wife, Lori Zappala Hardiman, "comes from a family of prominent western Pennsylvania Democrats," a report from a local Philadelphia TV station noted.

Casey faces Republican Lou Barletta, who was endorsed by President Trump about three months before the state's primary election this past May. Barletta was elected to the U.S. House in 2010—a Republican "wave" year—and was also rumored to be on Trump's short list for labor secretary during the transition.