And, of course, there’s no mystery in how the whole thing is going to end.

“This trial will end in a matter of days, not weeks,” Senator Lindsey Graham promised recently on Fox News. “And [Trump’s] going to be acquitted.”

Indeed, the president’s allies in the Senate seem set on stripping away any possible suspense—as do his opponents, for that matter. A Politico tally counts only six senators—the Republicans Mitt Romney, Lisa Murkowski, and Susan Collins; the Democrats Joe Manchin and Kyrsten Sinema; and the independent Angus King—whose final votes are in serious question. By and large, the significant majority of senators have made clear that they will vote with their party on whether to evict the president. Some have been more egregious in this predetermination than others: Graham and Senate Majority Leader Mitch McConnell, who has pitched his “total coordination” with the White House as a selling point, are at the far end of that spectrum. But partisanship is such that there is no doubt about the trial’s conclusion and very little margin of error in predicting the final vote.

Benjamin Wittes and Quinta Jurecic: Pelosi and McConnell are playing high-stakes poker

A twist ending isn’t necessary for a good drama, of course. Plenty of stories draw their power from the inevitable descent toward a tragedy—or a marriage—everyone knows is coming. The tension comes from wondering just how the characters will arrive at that point. Yet McConnell is doing his best to suck any narrative interest out of the process.

In a real trial, the members of the House of Representatives presenting the case for removal would be allowed to tell the whole story of Trump’s conduct—at least, whatever part of it they can tell without requiring testimony that would violate one privilege or another. That would mean they could call all of the witnesses who testified in the House impeachment proceedings and add to them key witnesses who declined to show up. They could seek documents that have not been turned over so far. And they could present all of this material as a coherent case, much the way a prosecutor tells a jury a story by presenting a sequence of witnesses. And in a real trial, the president’s lawyers—who have complained that the House proceedings did not allow them to call witnesses—would be able to present a case of their own. All of this would result in actual suspense over the question of what information would compose these cases. What new things would we learn? And from whom would we end up hearing?

In this case, the live question is not whether we will hear a complete presentation of the evidence and the available witnesses but whether we will hear any witnesses at all. The answer to that question is, in fact, the only matter of significant doubt as the trial gets under way.