“The senate collectively has the power to compel the attendance of absent senators and the Senate collectively acts by its majority and Mitch McConnell is the majority leader. So he has the ability,” former Senate parliamentarian Alan Frumin said. “If push comes to shove, compelling means arresting. ”

It could even mean sending the chamber’s Sergeant at Arms to Iowa to collect truant senators if need be, said Frumin, who spent 19 years in the position and is one of the foremost experts in the rules and procedures of the body.

While Democratic senators might ordinarily relish their Constitutional obligation to sit in judgment over the polarizing billionaire, the trial couldn’t come at a worse time in the 2020 Democratic primary calendar. The Iowa caucuses are Feb. 3, with the New Hampshire primary coming just eight days later. South Carolina and Nevada will follow before the month is out. The candidates have invested millions of dollars in the states, and many have pinned their future on strong showings.