Despite making public assurances that he would fulfill their Constitutional obligations as impartial jurors in President Trump’s impeachment trial, Louisiana Senator Bill Cassidy joined a large number of GOP Senators in leaving the Senate Chambers for prolonged periods of time, while crucial evidence was introduced against the President.

This afternoon, Michael McAuliff, Congressional reporter for the New York Daily News, tweeted that he counted “21 empty seats on the GOP side, a couple hours into [Representative] Schiff’s presentation.” Jon Ward of Yahoo News also observed that “more than a dozen” GOP Senators had left the chamber and were in the cloakroom, only two hours into Representative Schiff’s case against Donald Trump. Rep. Schiff (D-Calif.) was chosen by the Democrats as a lead impeachment prosecutor.

McAuliff noted particularly that Senator Cassidy was absent for a long period of time, as were Republican Senators Lindsey Graham (R-S.C.) and Senator James Risch (R-Idaho). Remarkably, Senator Risch was also caught sleeping during the hearing on Monday.

Last week, all one hundred United States Senators were sworn in as jurors by the Chief Justice for the United States Supreme Court. Senator Cassidy, taking this oath, swore that “in all matters appertaining to the trial of the impeachment” of the President, he would be impartial.

Senator Cassidy made a statement in a press release in December, affirming that “the Senate will offer President Trump a fair process” and that he looked forward to “fairly judging the facts.” Yesterday he tweeted: “I intend to be a fair and impartial juror and consider the facts, not let partisan distractions get in the way.”

Under the agreed-upon Senate rules for impeachment, the House of Representatives have no more than 24 total hours, over three days, to make their case as to why Donald Trump violated the United States Constitution and should be removed from office. Under Article I, Section 3, Clause 6 of the Constitution, the Senate alone has the power to convict the President following impeachment, and they must do so by a two-thirds majority.

The fact that Senator Cassidy and several others charged with making this determination were absent for a substantial portion of the prosecution’s case caused many to opine on Twitter that they should be reprimanded or disqualified as jurors.

Newsweek noted that while the oaths of impartiality are not legally binding, the Senate could elect to impeach one of its own for violating the rules. The rules do not explicitly require the Senators to be seated during the trial, but Senate Majority Leader Mitch McConnell (R-Ky.) and Senate Minority Leader Chuck Schumer (D-N.Y.) both told their camps they needed to be in attendance at all times – which Senator Cassidy failed to do.

In a recent Pew Research poll, a narrow majority of Americans (51 percent to 46 percent) would like to see the President removed from office, but almost two-thirds (63 percent to 36 percent) of Americans believe that Donald Trump has “definitely” or “probably” broken the law while either campaigning or serving in office.

McAuliff was surprised that Senator Cassidy was absent for so long, because he looked like “the most active note-taker” on the GOP side – at least prior to leaving the chamber in the middle of the hearing.

The fact that Senator Cassidy and other lawmakers were absent during a crucial part of the trial was not ignored by legal blogs. Law & Crime remarked that one-third of all GOP Senators missed the same crucial evidence in the President’s trial. They also contrasted Senator Cassidy’s absence with his promises to “listen to both sides with an open mind.” Bradley Moss, a national security attorney, observed that, of all jurors in all trials, only in the Senate can “‘jurors’ get to stand up and walk out during the prosecution’s presentation of the case.”

Conservative pundit Bill Kristol likened the behavior of Senators like Cassidy to endorsing a mockery of a trial. “I grew up reading about show trials in authoritarian nations abroad,” Kristol said on Twitter.” “I didn’t expect to see one of our two major parties endorse a show trial here in the U.S. Capitol.”