Executive privilege does not apply:

In a sealed decision that could clear the way for other top Trump White House officials to answer questions before a grand jury, Chief U.S. District Judge Beryl A. Howell ruled that former Pence chief of staff Marc Short probably possessed information important to the Justice Department’s criminal investigation of the Jan. 6, 2021, attack on the Capitol that was not available from other sources, one of those people said.

Trump appealed, but the U.S. Court of Appeals for the District of Columbia Circuit refused to postpone Short’s appearance while the litigation continues, the people said, signaling that attempts by Trump to invoke executive privilege to preserve the confidentiality of presidential decision-making were not likely to prevail.

I've noticed several friends asking, "What is Merrick Garland waiting for?" He's not waiting. Hasn't been waiting. A true bill of indictment handed down by a Grand Jury is the proper approach in any controversial prosecution, and this one is without a doubt the most controversial one. No former/current President has ever been prosecuted for a crime, so we're in unexplored territory here. Of course this is taking a long time, because Trump is fighting every move the DOJ makes:

Grand jury matters are typically secret, but The Washington Post has reported that prosecutors are working with grand jurors and looking extensively at the actions of Trump and his advisers in the period between the November 2020 election and Jan. 6, 2021. Short’s case came to light on Sept. 22 after Trump attorneys M. Evan Corcoran, Timothy C. Parlatore and Rowley were seen at federal court in Washington when there were no publicly scheduled matters, along with a lead Jan. 6 federal prosecutor, Thomas Windom.

According to people familiar with the matter, Short had appeared before a grand jury in downtown Washington in July, but declined to answer certain questions after Flood argued the communications of top White House advisers are protected — and presented written documentation from Trump’s lawyers that they were asserting executive privilege.

The Justice Department asked the court to intervene, urging Howell to override Trump’s claim and to compel Short to answer questions about his communications with Trump, one person said. After arguments Sept. 22, Howell granted the government’s motion, the people said, but because the investigation and an appeal are ongoing, it is unclear if or when a redacted opinion will become public.

One of the reasons Trump fought this particular battle is that Marc Short does not seem inclined to lie for the orange buffoon:

The certification vote on Jan. 6 had become a focus for Trump, who saw it as a last-ditch chance to retain the presidency despite his loss at the polls.

Marc Short, who was Pence's chief of staff, said in videotaped testimony that Pence told Trump "many times" that he did not have the authority to stop the vote certification in Congress as the Republican president sought.

Gregory Jacob, an attorney for Pence, said the main proponent of that theory, attorney John Eastman, admitted in front of the president two days before the attack that his plan to have Pence halt the procedure would violate the law. Eastman had argued that Pence could reject results from certain states if he thought they were illegitimate, giving Republicans in those states an opportunity to declare Trump the victor despite the actual vote count.

Advisers to Pence told the committee that idea had no basis in law.

"It is breathtaking that these arguments even were conceived, let alone entertained by the president of the United States," former U.S. Appeals Court Judge J. Michael Luttig, an informal Pence adviser, said.

Breathtaking is an understatement. Trump was warned repeatedly such an attempt was against the law, but that didn't cause him to even pause and reflect. Knowingly engaging in criminal behavior checks off the "intent" box, so let the Grand Jury do their jobs.