Former Vice President Mike Pence has filed a motion seeking to block a subpoena for his testimony about the events surrounding the Jan. 6, 2021, attack on the Capitol.

CNN first reported on Monday that Pence filed a motion on Friday night asking a judge to block the subpoena for him to testify before a federal grand jury. A spokesperson for Pence declined to comment.

The filing comes a few weeks after Pence publicly stated he planned to fight a subpoena to testify before a grand jury investigating former President Trump’s efforts to overturn the 2020 election, saying he was prepared to go to the Supreme Court if necessary.

Special counsel Jack Smith, who is overseeing separate investigations into Trump’s conduct around Jan. 6 and his handling of classified documents, issued the subpoena.

Pence and his team plan to argue that serving as the former president of the Senate essentially makes him a member of the legislative branch, and he would therefore be shielded from the subpoena under the “speech and debate” clause of the Constitution.

Pence has said Trump was “wrong” to try to overturn the election, and he has been adamant that the vice president does not have the power to unilaterally reject electoral results.

“But that said, under the Constitution, in this moment, I believe my duty is also clear,” he said in Iowa last month. “And that is, the Constitution prohibits an executive branch from summoning anyone into court for their legislative actions or duties, and on the day of Jan. 6, I was acting as president of the Senate, presiding over a joint session described in the Constitution itself.”

Pence’s efforts to resist the subpoena are separate from legal filings by Trump’s team seeking to block the former vice president’s testimony on grounds of executive privilege. 

The former vice president is mulling a 2024 presidential bid, visiting early primary states including Iowa, New Hampshire and South Carolina. He is expected to make a final decision in the coming months.

Running for the GOP nomination would pit Pence against Trump, who has continued to falsely claim the 2020 election was stolen and fraudulent as he campaigns to return to the White House.