It’s the president’s prerogative to make nominations to the federal judiciary. It doesn’t matter if it’s President Obama or President Trump. The nominees should be evaluated for their qualifications. Partisan politics should be out of the equation.

But partisan politics are almost inevitably in the equation. And they are muddling up the nomination of federal prosecutor Ryan Bounds, born in Hermiston, to sit as a judge on the 9th U.S. Circuit Court of Appeals.

Oregon’s Democratic Sens. Jeff Merkley and Ron Wyden have sent a letter to President Trump vowing to attempt to block the nomination. Why is Bounds out? It’s not his qualifications. It’s partisanship. They claim Trump is being partisan, and they are being bipartisan.

They want Trump to direct all potential nominees to Merkley’s and Wyden’s selection committee for vetting. They insist that it is Oregon’s “long bipartisan tradition” to work together “to identify the most qualified candidates for judicial vacancies.” And as senators, they take the task of advice and consent seriously. “Disregarding this Oregon tradition returns us to the days of nepotism and patronage that harmed our courts and placed unfit judges on the bench,” their letter says.

Merkley and Wyden might be able to block a judicial nomination because of Senate tradition. In the past, senators could stop a nomination by not returning a “blue slip” for a nominee.

Failure to return a blue slip has not always blocked a nominee. For instance, it didn’t between 1979 and 1989, according to the Congressional Research Service. And Senate Judiciary Committee Chairman Chuck Grassley, an Iowa Republican, has indicated he might not allow a blue slip blockade.

Merkley has shown curious behavior when it comes to Senate traditions. He led an effort to undo Senate traditions allowing filibusters for most presidential appointees when Obama was president. Under President Trump, he has shown a renewed interest in traditions.

Merkley and Wyden have turned the Bounds nomination into a debate over process when it should be a debate about qualifications for the job.