'we could be in uncharted territory. Indeed, 1895 was the last time a Democratic president nominated a justice facing a Republican Senate (44 Republicans joined 40 Democrats and six senators of other parties to approve Grover Cleveland's nomination of Rufus Peckham). Since then, every other Democratic president with a Supreme Court vacancy faced a friendly Senate.
There are, of course, several examples of the reverse dynamic, where Republican presidents faced Democratic Senates: Dwight Eisenhower, Richard Nixon, Gerald Ford, Ronald Reagan, George H. W. Bush. As we know, the nominees weren't all successful (Robert Bork) but the presidents eventually found nominees that Senate Democrats considered acceptable (Justice Anthony Kennedy).'