As the Senate impeachment trial began in earnest Tuesday, President Trump’s lawyers decried the lack of “fundamental fairness and due process” in the House investigation and blasted Democrats for a “wholesale trampling of constitutional rights,” as White House counsel Pat Cipollone put it.

Later, one of the House Democrats who is prosecuting the case against Trump argued that Americans are familiar with trials through TV shows or even personal experiences, and thus would expect the witness testimony the Democrats want to hear in the Senate trial. “All we’re asking for today is to give the American people the trial that they expect,” said Rep. Sylvia Garcia (D-Tex.), a former judge herself.

The Senate proceeding now underway may be called a “trial,” with senators serving as jurors and Chief Justice John G. Roberts Jr. as judge. But it is distinct from a traditional criminal trial in important ways that are worth pointing out as each side makes its case by drawing comparisons to ordinary trials.

1. The biggest difference is what’s at stake

The consequences for a criminal defendant facing conviction are prison time, loss of property or even a death sentence. For that reason, the Constitution, and state and federal law, guarantee a long list of protections, including the right against self-incrimination and the right to a lawyer.

None of those protections apply when it comes to a House impeachment inquiry or a Senate trial, even though Trump’s legal team repeatedly suggested the president had been denied due process.

“Impeachment is essentially a glorified process to determine whether someone should be fired from their job,” said Ilya Somin, a professor at the Antonin Scalia Law School at George Mason University.

2. Senators as jurors and a pledge to do ‘impartial justice’

In a typical trial, there are safeguards to ensure jurors are impartial. At the start of the Senate proceedings last week, Roberts asked lawmakers to rise to take an oath of impartiality. That’s where the similarities end.

Legal observers joked that every one of the 100 senators would likely have been struck for bias from the pool of potential jurors in an ordinary trial. Four senators — Bernie Sanders (I-Vt.), Amy Klobuchar (D-Minn.), Elizabeth Warren (D-Mass). and Michael F. Bennet (D-Colo.) — are in the running for the Democratic nomination to replace President Trump. The jury foreman for the trial, Majority Leader Mitch McConnell (R-Ky.), has said there is “zero chance” the president would be removed from office, and promised “total coordination” with the White House and Trump’s defense team.

During a criminal trial, judges admonish jurors daily to avoid talking to any of the lawyers involved in the case and to refrain from reading media coverage or giving interviews. In contrast, during a brief recess Tuesday, Senate Republicans made a point of greeting members of Trump’s legal team. Sen. Charles E. Grassley (R-Iowa) made an almost complete circuit around the defense table, as McConnell spoke to Cipollone, the White House counsel.

Senators in both parties used breaks in the official action to give media interviews and to respond on Twitter to the proceedings.

“It’s truly bonkers,” Preet Bharara, the former U.S. attorney for the Southern District of New York, said of the analogies to traditional trials.

“In a real criminal trial, jurors are not even allowed to know the defendant much less have an opinion of him, much less read stories, much less have a subset of them who want to replace the defendant.”

3. The chief justice as trial judge

Like a judge presiding over a courtroom, Chief Justice John G. Roberts Jr. wields a gavel and is seated prominently at the dais of the Senate chamber. Once questioning begins, Roberts will play an active role, reading aloud written questions from senators to the House managers, the president’s lawyers or witnesses.

The rules also give Roberts the power to make calls on questions of evidence, including on the relevancy of witnesses. He can make initial rulings, but he does not have the final word, and can be overruled by a majority of senators.

In a traditional trial setting, the judge controls the courtroom and has wide discretion to makes rulings on which evidence and witness testimony jurors can consider in their deliberations.

Because Roberts is concerned about the Supreme Court being seen as nonpartisan, he may be wary of taking sides when it comes to making controversial calls. In that way, the senators sitting as jurors are more powerful than the judge in an impeachment proceeding, and the chief justice has less power than a presiding judge typically would in a the courtroom.

4. Standards of proof and a vote to convict

In a criminal trial, jurors are instructed on the specific standard of proof required to find a defendant guilty. When a defendant’s life and liberty are at stake, the prosecutor’s burden is high and must be proved “beyond a reasonable doubt.”

In an impeachment trial, however, senators are not bound by any such standard. A vote of two-thirds of senators present is required for a conviction, but the question of whether to convict has historically been a political choice for individual senators.

“When deciding questions of impeachment and removal,” according to a 2019 Congressional Research Service report, “historical practice seems to indicate that members need be convinced only to their own satisfaction.”