While conservatives like Mr. Whelan laud Mr. Trump’s nominees as likely to rule according to the text and original meaning of the Constitution, liberals like Nan Aron, president of the Alliance for Justice, say that the Trump administration has been packing the courts with “right-wing extremists” who are hostile to reproductive rights, gay rights and civil rights, and excessively deferential to corporate power.
“The fear is that they will be able to cement their hold over the judiciary,” she said.
After the midterm vote, Mr. McConnell will have some breathing room from the razor-thin margins he has been working with — Justice Brett M. Kavanaugh was confirmed 50 to 48, with one Republican, Senator Lisa Murkowski of Alaska, defecting. The problem was also illustrated by the White House’s withdrawal in July of an appeals court nominee, Ryan W. Bounds, after Senator Tim Scott, Republican of South Carolina, objected to him over racially charged writings. Without Mr. Scott’s support, Mr. McConnell lacked sufficient votes to confirm Mr. Bounds.
Republicans increased their margin in the Senate by defeating Democratic senators in conservative-leaning states who had voted against confirming Justice Kavanaugh, like Joe Donnelly of Indiana, Heidi Heitkamp of North Dakota, Claire McCaskill of Missouri and, apparently, Bill Nelson of Florida, although he has asked for a recount.
By contrast, a rare Democrat who survived re-election in a state that Mr. Trump won in 2016, Senator Joe Manchin of West Virginia, had broken with his party to vote for Justice Kavanaugh.
In 2020, Republican incumbents will be running in states where Democrats have a shot, including Colorado, Maine and North Carolina. But Democrats will have vulnerable incumbents up for re-election, too — especially Senator Doug Jones, Democrat of Alabama, who won a special election in the deeply conservative state last year against an opponent who had been accused of a pattern of sexual misconduct against minors.
Donald F. McGahn II, Mr. Trump’s former White House counsel and the chief architect of his judicial nominations until he left the administration last month, said that the red-state Democrats who voted against Justice Kavanaugh had “paid a price,” cementing the judicial strategy Mr. Trump and Republicans have followed.
“President Trump ran on judges. He has delivered on judges. And last night vindicates what he has done and shows that it will continue to happen,” he said. “And the overwhelming night the Republicans had in the Senate is going to pay dividends on judges even beyond this election. When one looks at the election map in 2020, it’s easy to see that Republicans are in an excellent position to maintain Senate control regardless of what happens elsewhere on the ticket.”