For only the third time in this country’s history, a president has been impeached. It now will be up to the U.S. Senate to determine whether President Donald Trump becomes the first one to be convicted by trial in the Senate and removed from office.

The Senate impeachment trial was designed by the founders to be a serious, deliberative proceeding. For that reason, senators acting as jurors take an oath to do “impartial justice.” In deciding the case before them, they are free to question witnesses. A conviction must be delivered by a supermajority, to foster consensus. In another move intended to convey impartiality, the chief justice of Supreme Court presides.

At least that’s how it’s supposed to work. But what is left of all those high-minded intentions when two key figures, Senate Majority Leader Mitch McConnell and Senate Judiciary Committee Chairman Lindsey Graham, have already declared their full cooperation with the defendant?

It is unsettling that McConnell and company are so emboldened that they don’t even feel the need to go through the motions of a fair trial. This is where, at least in theory, the president should be able to make his strongest defense against the charges made by the House. To call the witnesses that would clear his name and attest that the actions he took were not for his personal gain. But now, after months of bitter complaints that Trump had no chance to defend himself, after absurd, over-the-top outrage that he has been treated worse than a witch at the Salem trials, worse than Jesus Christ at the hands of Pontius Pilate, the defense apparently intends to produce … nothing.

And really, there is no need when the fix is in. In a recent interview with Fox News host Sean Hannity, McConnell said there was “zero chance” the president would be removed from office, and vowed “total coordination” with the White House and the Trump defense team.

Impeachment and potential removal of a president is a rare and grave matter and deserves to be treated as such, not dismissed as simply another partisan maneuver. Whether McConnell acknowledges it or not, the House did its due diligence, with hearings in which witnesses corroborated one another on information that led to the charges. Trump blocked some of the most important witnesses and attempted to intimidate those who did testify — itself an obstruction of a legal and valid investigation.

The founders intended impeachment as a necessary curb on a rogue leader, because even more important than the presidency are the carefully constructed checks and balances that undergird our government. They hardly could have imagined a circumstance in which senators would yield that power in favor of protecting the very leader they are duty-bound to hold to account.

If the Senate acquits Trump, so be it. No president has ever been convicted. House Speaker Nancy Pelosi is withholding the articles of impeachment until the Senate shows it will conduct a fair trial, with documents and witnesses. Only then, she said, will the House appoint managers who would handle the prosecution. McConnell’s discomfort is understandable. But lasting damage will be done if the Senate conducts only a show trial with a predetermined outcome that would be an acquittal in name only.