J. Scott Applewhite/AP/FILE
CNN  — 

Former Vice President Mike Pence is expected to fight a recent subpoena from the special counsel investigating former President Donald Trump’s post-2020 election activities based on the grounds that he was president of the Senate at the time and therefore shielded from the order, sources familiar with the matter tell CNN.

Pence is expected to address the subpoena and his response to it during a trip to Iowa on Wednesday, according to a source familiar with his plans. His decision to fight the subpoena comes as the former vice president is mulling a 2024 presidential bid.

Pence has been subpoenaed by Jack Smith, the special counsel investigating Trump and his role in January 6, 2021, a source familiar with the matter told CNN. Smith’s office is seeking documents and testimony, the source said. Investigators want the former vice president to testify about his interactions with Trump leading up to the 2020 election and the day of the attack on the US Capitol.

Pence’s decision to fight the subpoena is likely to drag out his legal entanglements, something that many advisers had hoped would be cleared up by the time he announced his likely bid for president.

However, the move could allow for Pence to avoid the optics of willingly participating in an investigation into his former boss at the hands of the Department of Justice, which Republicans have sought to paint as politicized.

The decision could also help the former vice president avoid being pitted against Trump once again, after a lawyer for the former president confirmed Sunday that Trump intends to assert executive privilege in an effort to limit any Pence testimony, a source close to Pence noted. Pence has often worked to downplay the tension between he and the former president as he inches towards a presidential run against his former boss, including largely defending Trump and touting the administration’s achievements in his new memoir.

Pence’s team, according to a source, had previously indicated to the Justice Department that he’d be open to answering questions if they were limited to the matters he had previously discussed publicly, including in his book.

The subpoena marks an important milestone in the Justice Department’s two-year criminal investigation, now led by the special counsel, into the efforts by Trump and allies to impede the transfer of power after he lost the 2020 election. Pence is an important witness who has detailed in a memoir some of his interactions with Trump in the weeks after the election, a move that likely opens the door for the Justice Department to override at least some of Trump’s claims of executive privilege.

Pence’s intentions to resist the subpoena were first reported by Politico.

The prospect of Pence fighting the special counsel’s subpoena in court comes as several other witnesses in the Justice Department’s investigations encircling Trump are already in secret legal battles over DOJ’s demands for information from them. Those legal battles have played out under seal, keeping out of view the details of what exactly the department is seeking from members of Trump’s inner circle and what arguments are being made for withholding that information. It is unclear how much will be made publicly known about the circumstances of Pence’s dispute with the special counsel over the subpoena – beyond the response Pence is expected to issue Tuesday.

Pence is expected to make arguments raising the Constitution’s Speech or Debate Clause, according to a source. The clause protects legislators from certain law enforcement actions if the conduct in question is related to their legislative duties. Lawmakers have tried to use the Speech or Debate Clause to resist participating in the House investigation into the January 6, 2021, insurrection at the US Capitol. Sen. Lindsey Graham also invoked the clause to challenge a subpoena in the Fulton County, Atlanta, investigation into 2020 election meddling, but the South Carolina Republican was ultimately ordered by courts to appear for testimony in that probe. Among the sealed proceedings related to the Justice Department’s investigations is a secret dispute with Rep. Scott Perry, concerning information DOJ is seeking from the Pennsylvania Republican’s phone, where Perry is also raising Speech or Debate Clause claims. That case is currently before the DC Circuit US Court of Appeals.

This story has been updated with additional details.

CNN’s Katelyn Polantz and Evan Perez contributed to this report.