Senate Judiciary Committee Chairman Charles E. Grassley (R-Iowa) speaks on Capitol Hill on Thursday. (Jacquelyn Martin/AP)

Senate Judiciary Committee Chairman Charles E. Grassley (R-Iowa) said Tuesday that he would not allow a Supreme Court vacancy to be filled in 2020, a position that puts him at odds with the Senate’s top Republican on an issue that has inflamed partisan tensions for more than two years.

In an interview with Fox News Channel’s Martha MacCallum, Grassley was asked whether he believes the Senate should take up a hypothetical Supreme Court nomination during 2020, when President Trump will be up for reelection.

“If I’m chairman, they won’t take it up,” said Grassley, whose committee is charged with holding hearings on Supreme Court nominees. “No, because I pledged that in 2016, that if the ball’s the same as it is. Now, if somebody else is the chairman of the committee, they’ll have to decide for themselves. But that’s a decision I made a long time ago.”

In 2016, Senate Majority Leader Mitch McConnell (R-Ky.) blocked the consideration of President Obama’s third nominee to the Supreme Court, Merrick Garland. At the time, McConnell said he was blocking Garland because voters “should have a say in the court’s direction” on Election Day. The move infuriated Democrats, who accused Republicans of abandoning their constitutional duty to advise and consent.

But on Monday, McConnell cited a different calculus, telling reporters in Louisville that opposition parties in control of the Senate do not traditionally confirm high court nominees during presidential election years.

McConnell’s remarks were viewed as a signal that he would be open to filling a potential Supreme Court vacancy in 2020.

As chairman of the Judiciary Committee, Grassley would play a key role in the confirmation process. Yet the Iowa Republican has notably declined to shut the door to a potential switch to the Finance Committee next year.

If Grassley does become chairman of the finance panel, his successor on the Judiciary Committee would probably be Sen. Lindsey O. Graham (R-S.C.).

For his part, Graham said last week that if an opening arises during the final year of Trump’s term and the presidential primary is underway, “we’ll wait until the next election.”