Sen. Ron Johnson (R-Wis.) called on Supreme Court Chief Justice John Roberts to “rein those judges in” who have issued orders blocking parts of President Trump’s agenda.

“You’ll notice the activist judges, that the radical leftists, that the super legislators on the courts are issuing national injunctions against what he’s [President Trump’s] trying to do, what we wanted him to do, what the people elected him to do,” Johnson said, speaking to a crowd of constituents who gathered to hear tech billionaire at a town hall in Wisconsin on Sunday evening.

“We can’t let that continue,” Johnson said. “Now, what should happen is, is John Roberts ought to rein those judges in. He ought to take care of his own branch of government.”

Johnson’s remarks come as some Republicans have taken steps to target judges making decisions that have slowed the Trump administration’s efforts to advance his agenda.

Several Republican lawmakers have filed impeachment resolutions against certain judges. Trump, too, has called to impeach at least one district judge, James Boasberg, who issued a nationwide injunction to block his administration from using the Alien Enemies Act to deport Venezuelan migrants.

Impeachment is seen as a largely futile effort, given the near-zero chance that at least 14 Senate Democrats would join Republicans in convicting and removing any of the judges.

Calls to impeach federal judges who have issued disappointing decisions have concerned legal experts, including Roberts, who issued a rare statement earlier this month warning against calling for impeachments.

“For more than two centuries, it has been established that impeachment is not an appropriate response to disagreement concerning a judicial decision,” he wrote in the statement.