If the people who are subpoenaed do not comply, you send them to fucking jail:
The select committee investigating the Jan. 6 Capitol riot threatened on Friday to pursue criminal charges against Stephen K. Bannon, the former chief strategist to President Donald J. Trump, for refusing to comply with its subpoena, announcing it would consider initiating criminal contempt of Congress proceedings.
In a statement after Mr. Bannon informed the panel that he would not cooperate in the inquiry, the panel’s leaders said they would “swiftly consider” the contempt referral, raising the prospect of what could be a prolonged legal battle over what could be crucial evidence in the investigation.
The committee has ordered four former Trump administration officials — Mr. Bannon; Mark Meadows, the White House chief of staff; Dan Scavino Jr., a deputy chief of staff and Kash Patel, a Pentagon chief of staff — to sit for depositions and furnish documents and other materials relevant to its investigation.
It’s not like it is without precedent- google Susan McDougal. Republicans loved it then.