“This is a persuasive exercise,” says Frank O. Bowman III, a law professor at the University of Missouri. “You need to persuade [the public] not only that the president did XYZ, but that what he did is of sufficient gravity to merit his removal.”

The public hearing, which is scheduled for December 4, follows historical precedent. During the impeachment of President Bill Clinton in 1998, the House Judiciary Committee held a similar hearing on the background and history of impeachment. The committee members called on 19 experts to determine whether Clinton’s alleged conduct justified impeachment, including 10 who testified on the Republican side, eight on the Democratic side, and one joint witness, the constitutional-law expert Michael Gerhardt.

Such a hearing “provide[s] the members of the committee with some expert guidance,” Gerhardt, now a law professor at the University of North Carolina, told me in an interview. “People on the committee will be the ones who make the final judgment, but they really want and perhaps need some educated, informed judgment about what the law is, and that will provide a foundation for them.”

Read: The question Democrats have to answer before they can impeach

It’s still unclear which witnesses will be called to testify. But both Gerhardt and Bowman told me they expect the hearing to operate similarly to the one held in 1998. The members will likely ask questions about the Intelligence Committee’s forthcoming report, which will compile all the evidence gathered by Democrats throughout their two-month impeachment inquiry. Witnesses will offer definitions of misdeeds such as “bribery” and “high crimes and misdemeanors,” which are among the impeachable offenses listed in Article II of the Constitution. It’s likely, too, that there will be a discussion of where obstruction of justice and the Trump administration’s flouting of congressional subpoenas fit in.

Even after two weeks of public hearings, Americans are deeply divided on impeachment, and not a single Republican in either the House or the Senate publicly supports it. So Democrats are viewing this hearing as one of the last opportunities they have to convince congressional Republicans that impeachment is warranted. “Ideally, [committee members] would conceive their role as educative at this point, of explaining to the country why it is the facts we know are impeachable and on what grounds,” Bowman told me.

“We often say ‘high crimes and misdemeanors,’ but we say this with no understanding of what that actually means,” said one Democratic aide to a member on the Judiciary Committee, who spoke on the condition of anonymity. Impeachment is a fundamentally political process, not a legal one.

But the hearing is far from an easy win for Democrats. They’ll need to nail their approach, Bowman said, deciding ahead of time what kind of case they want to make against the president. And they’ll need to think about how to frame the president’s alleged quid pro quo with Ukraine, to show how it falls into the category of “high crimes and misdemeanors.” Committee members will also need to decide the extent to which they’ll broaden the scope of the inquiry to include issues such as Russian election interference and potential violations of the Constitution’s emoluments clause. It will be a challenge: Democrats have a wealth of grievances against the president, and, given the party’s stated goal to wrap up the process before the end of the year, there’s not much time for them to arrange it concisely.