Republican senators hope to gain new insight into how the White House was governed during President Biden’s reported cognitive decline by hearing from experts on White House operations and constitutional law, including a former press secretary for President Trump, Sean Spicer. Most — if not all — of the Democrats on the Judiciary Committee, which is holding Wednesday’s hearing, are expected to skip the event. 

The 91-year-old chairman of the panel, Senator Grassley, is not hosting this hearing on Wednesday. Instead, it will be led by Senators Cornyn and Schmitt. The meeting is titled, “Unfit to Serve: How the Biden Cover-Up Endangered America and Undermined the Constitution.”

“Those closest to the President and the mainstream media did everything they could to hide this truth,” Mr. Schmitt said in a statement. “It’s time to expose how a cadre of Biden aides and family members were the de-facto commander-in-chief, while President Biden was sidelined.” Mr. Cornyn says it’s time to get to the bottom of what he calls a “conspiracy that aides and family orchestrated to stay in power despite the president being, according to a bestselling book, “Original Sin,” non compos mentis.

The three witnesses for Wednesday’s panel are conservatives with insight into White House operations and governance: Mr. Spicer; a former Idaho solicitor general and Trump aide, Theodore Wold; and a former justice department official, John Harrison, who is now a law professor at the University of Virginia. 

Mr. Schmitt has launched an email tipline for whistleblowers to come forward with information about Mr. Biden’s cognitive abilities while he was president, and about the White House staffers who insulated him from all but a handful of close family members and aides. 

Mr. Spicer most recently served in government as Mr. Trump’s first White House press secretary. He is now an author, public speaker, and host of a popular YouTube show.

Mr. Wold, meanwhile, has climbed the ranks of the conservative legal world. He has served as a fellow at both the Claremont Institute and Hillsdale College after working as a law clerk for Judge Janice Rogers Brown for the U.S. Court of Appeals for the District of Columbia. 

Later in his career, Mr. Wold spent more than three years working in the first Trump administration. He was also a senior aide to Senator Lee on the Judiciary Committee. 

Mr. Harrison is a conservative of a different era, having held positions in the Department of Justice under both President Reagan and the elder President Bush. He has been at the University of Virginia since 1993, where he now teaches courses on constitutional law, the legislative process, and civil procedure, among other things. 

Democrats are largely expected to skip the Senate hearing, which so far has taken a back seat to House Republicans’ more aggressive probe. The top Democrat on the Judiciary Committee, Senator Durbin, told the Washington Examiner on Tuesday that he will offer opening remarks and then leave the room. His staff later said that they are unaware of any Democratic member who is planning to attend the hearing for an extended period of time. 

The House has launched an aggressive investigation into the alleged cover-up — issuing requests for testimony and subpoenas to the small circle of Biden aides identified in journalistic accounts as having had access to the president. The chairman of the Oversight Committee, Congressman James Comer, told the Sun last week that four of Mr. Biden’s top aides have already agreed to sit for interviews with his panel over the course of the next six weeks.