Michael J. Gerhardt is a law professor at the University of North Carolina and author of “Impeachment: What Everyone Needs to Know.”

A presidential impeachment tests everyone involved, including the person designated by the Constitution to serve as presiding officer in this case, Chief Justice John G. Roberts Jr. I believe the House was justified in impeaching President Trump, and the Senate would be similarly justified in convicting and removing him from office. But I also believe that those calling on the chief justice to prevent the Senate trial from becoming a farce or a whitewash suffer from a fundamental misunderstanding of the role that Roberts should play.

These wishful thinkers assume the word “preside” means that the chief justice will preside as a judge does in a real court of law: issuing subpoenas, compelling testimony, ruling on evidentiary and procedural motions. They want Roberts to follow the lead of Chief Justice Salmon P. Chase, who presided over the impeachment trial of President Andrew Johnson in 1868. Chase was aggressively involved in shaping the Senate’s impeachment rules to give himself greater authority and trying to steer the trial toward an acquittal.

A closer look at the constitutional language and the origins and practice of impeachment reveals that these presumptions misread the intent of the Framers and the history and nature of the impeachment process. The constitutional directive that the chief justice “shall preside” does not mean that he will be a presiding judge. “Preside” must be understood in the context of an impeachment trial, not a trial in a court of law. And impeachment trials are not legal proceedings; they are political proceedings with senators as the ultimate decision-makers.

James Wilson, a Pennsylvania delegate at the constitutional convention and one of President George Washington’s first Supreme Court appointments, explained in 1791 that impeachments are “confined to political characters, to political crimes and misdemeanors, and to political punishments.” Alexander Hamilton explained that the framers chose the Senate to be the “judges” and ultimate decision-makers because senators would not be “tied down” by “strict rules.” Senators are not bound by the rules of evidence or the rules of criminal procedure — only by the special impeachment oath they take to “do impartial justice.” Senators, unlike real judges, are politically accountable.

Imagine that the chief justice were to take an activist role — for example, ruling on whether Hunter Biden’s testimony is relevant. Where would he look for guidance on how to decide? Not to any law, because no law applies here to help the chief justice resolve such issues before him. If 51 or more senators say Biden should testify, he testifies. Any ruling Roberts makes can be overturned by a bare majority of the Senate.

The Framers chose the chief justice to preside in presidential impeachment trials for two reasons that had nothing to do with his powers or expertise. The first was purely ceremonial and symbolic: His presence brings solemnity to the occasion.

The other reason was to avoid the conflict of interest inherent in having the usual presiding officer of the Senate in charge, the vice president. This conflict was even more acute under the original Constitution, in which the vice president was not the president’s political ally but rather the opponent who finished second. Thus, as originally conceived, impeachment trials really did upend elections since the ousted president would be replaced by the person he defeated.

Placing someone else in charge was thought to remove that problem. The Framers offered no other insights into the chief’s role, except in otherwise providing that the Senate would have the power to determine its own rules for its proceedings, including trials.

The Senate’s rules and history make clear the Senate makes all important decisions in the trial. Chase had a hand in drafting the rules, giving himself power over “all questions of evidence and incidental matters,” and even to cast the tie-breaking vote when the Senate split evenly. But after Chase ruled on the competency of witnesses for the trial, two senators made a request that the Senate strip him of these broad powers. The motion failed, but barely. Chase tried to dilute the next one, which allowed any senator to appeal the ruling of the chair to the full Senate. It passed, and he was then overruled twice, leaving him embarrassed and scuttling the presidential run he had been planning.

In contrast to Chase, Chief Justice William H. Rehnquist was a model of restraint in presiding over President Bill Clinton’s impeachment trial. Rehnquist was never overruled — because he rarely ruled. When the trial ended, he proudly said, “I did nothing in particular, and I did it very well.”

Temperamentally, Roberts is likely to follow the example of Rehnquist, for whom he clerked. At his confirmation hearings, Roberts famously said, “My job is to call balls and strikes and not to pitch or bat.” He pointedly noted that no one came to a baseball game to watch the umpire. That does not sound like someone planning to become the center of attention in Trump’s trial.

Read more: