The dispute centers on a custom known as the blue-slip process, for the blue form that home-state senators use to communicate whether they approve of a judge’s nomination. The weight carried by blue slips has varied over the years, but Mr. Grassley has a looser policy than the last Democrat to lead the Judiciary Committee, Senator Patrick J. Leahy of Vermont.
Since Mr. Trump took office, Mr. Grassley has held hearings for a circuit court nominee from Minnesota and another from Wisconsin over the objections of a Democratic senator from each state, Al Franken of Minnesota and Tammy Baldwin of Wisconsin. The two nominees were later confirmed. And two weeks ago, the Senate was on the brink of confirming a nominee from Oregon, Ryan W. Bounds, even though the state’s senators, Ron Wyden and Jeff Merkley, both Democrats, opposed him.
Mr. Bounds had faced criticism over inflammatory writings from his college days, including a column in which he derided “race-focused groups” on campus and “race-think.” At the last minute, his nomination was pulled after Senator Tim Scott of South Carolina, the only black Republican in the chamber, raised concerns and would not support him.
That unexpected turn of events offered a reminder that Republicans have no room for error in pushing judges through the Senate if Democrats are united in opposition, given the chamber’s 51-to-49 divide and the continuing absence of Senator John McCain, Republican of Arizona, who has brain cancer.
Mr. Wyden quickly expressed hope that the fate of Mr. Bounds’s nomination would affect how Republicans handle judicial nominations in the future. But Mr. Grassley appears unmoved, at least regarding his policy on blue slips.
“That has nothing to do with it,” Mr. Grassley said. “Whether they had returned the blue slips or not, there were other issues, and that’s where we have to leave it.”
There are more judicial fights on the horizon. Senator Maria Cantwell, Democrat of Washington, quickly came out against a circuit court nominee from her state whom the White House announced this summer. Senator Sherrod Brown, Democrat of Ohio, opposes two circuit court nominees from his state, though Ohio’s other senator, Rob Portman, a Republican, supports them. Senator Bob Casey, Democrat of Pennsylvania, opposes a nominee from his state who has the support of Senator Patrick J. Toomey, a Republican.