Even the tired cliché about the pot calling the kettle black couldn’t adequately capture the irony when U.S. Sen. Charles Grassley, R-Iowa, last week accused Supreme Court Chief Justice John Roberts of fueling partisanship around the judiciary. “Physician, heal thyself,” Grassley said, admonishing Roberts in a speech.

Picking a fight with the Republican-appointed chief justice marks a bizarre twist in the Senate Judiciary Committee chairman’s refusal to consider a nominee to fill an opening on the court while President Barack Obama is in office.

Grassley’s remarks were in reference to a speech the chief justice had given shortly before Justice Antonin Scalia’s death. Roberts observed that the public wrongly believes that justices see themselves as Republicans or Democrats. Grassley shot back that perception is not because, as Roberts had contended, the confirmation process has been so politicized, but because “the justices’ decisions are often political and transgress their constitutional role.”

“In fact,” Grassley said, “many of my constituents believe, with all due respect, that the chief justice is part of this problem. They believe that a number of his votes have reflected political considerations, not legal ones.”

Far be it from me to defend Roberts’ voting record on the court, which included the disastrous 2010 Citizens United decision allowing corporations to spend unlimited amounts to influence election outcomes in the name of free speech. Roberts also authored the dissenting opinion in the 2015 court ruling that upheld same-sex marriage rights.

Since his appointment by President George W. Bush in 2005, Roberts has also voted against the use of race-conscious admission policies to achieve school desegregation, to strike down an animal cruelty law, to require that colleges that receive any federal funding must allow military recruiters on campus, and to uphold the partial birth abortion ban. A liberal he’s not.

But not according to Grassley, for whom Roberts’ cardinal sin must have been voting to uphold Obama’s Affordable Care Act. Grassley accused the court of drifting from the “constitutional text” and ruling on such hot button issues as “freedom of religion, abortion, affirmative action, gun control, free speech, and the death penalty,” based on individual policy preferences. And he blamed that primarily on justices appointed by Democrats.

It seems that for Grassley, only justices appointed by Republican presidents are capable of being impartial. But even then, some can’t be trusted because, like Roberts, they might occasionally drift from the conservative viewpoint.

Senate Democratic Leader Harry Reid fired back at Grassley for having, in Reid’s words, the audacity to accuse Roberts of being part of the problem. By refusing to give a hearing to Obama’s appointee, Judge Merrick Garland, “purely because he was nominated by a Democratic president,” Reid said, “Sen. Grassley has sacrificed the historic independence of the judiciary to do the bidding of the tea party and the Koch brothers.”

Grassley invokes his constituents to justify his intransigent stance. He denies being partisan but blasts a Republican-appointed justice for moving to the center. What could be a better illustration of partisanship — except maybe refusing to consider a Democratic president’s appointee?

So, many of us in Iowa and elsewhere await the election, wondering how Grassley will get out of the corner he’s painted himself into if a Democrat wins.