Former Vice President Mike Pence said Wednesday that he plans to “fight” a subpoena from the special counsel investigating Donald Trump’s actions surrounding Jan. 6, calling the demand for his cooperation “unprecedented and unconstitutional.”

“No vice president has ever been subject to a subpoena to testify about the president with whom they served,” Pence told reporters after speaking at a parents’ rights event in Minnesota.

Pence, who has written a book detailing some of his interactions with the former president leading up to the attack on the U.S. Capitol and done numerous interviews with reporters on the topic, said he was fighting the subpoena to testify before a grand jury on principle.

He also confirmed his unusual legal strategy — maintaining that he’s immune from testifying because of legal protections for lawmakers since he was acting as president of the Senate during the Jan. 6 Electoral College vote count rather than as a member of the executive branch.

“For me, this is a moment where you have to decide where you stand and I stand on the Constitution of the United States,” Pence said.

“On January 6th, President Trump was wrong. As I’ve said before, his words were reckless, and they endangered my family and everyone at the Capitol,” he said.

He added that despite Trump’s pleas to the contrary, “I had no right to overturn the election. But I would say in this very moment, it’s also wrong to establish a precedent where a legislative official can be called into court by the executive branch.”

“We’re prepared to take this fight into the court,” he said, adding that he expects Trump will also challenge the subpoena on executive privilege grounds.

Pence was subpoenaed by special counsel Jack Smith, a source familiar with the matter told NBC News last week.

Attorney General Merrick Garland appointed Smith in November to lead the Justice Department’s inquiries into Trump’s role in the riot as well as his handling of classified documents after he left office. The subpoena of Pence was related to the Jan. 6 investigation, the source said.

Despite numerous public statements about resisting Trump’s calls to reject the votes from numerous states on Jan. 6, Pence has resisted efforts to get him to testify under oath about his experiences.

In August of last year, Pence suggested he was open to speaking to the House committee investigating the riot at the Capitol, before backtracking in an interview with CBS News in November.

“I never stood in the way of senior members of my team cooperating with the committee and testifying, but Congress has no right to my testimony,” Pence said. “I’m closing the door on that.”