A Jan. 6 rioter was just sentenced to 20 years. If Trump wins, he could go free.

Judge Royce Lamberth of the D.C. Federal District Court sentenced David Dempsey, a violent Jan. 6 siege participant, to 20 years in prison on Friday. That is the second-longest Jan. 6 prison term imposed to date, just behind the 22-year sentence handed to Enrique Tarrio, head of the extremist Proud Boys, who spearheaded the Capitol siege. Judge Lamberth was appointed to the bench decades ago by President Ronald Reagan.

Dempsey’s 20-year term reminds those who are committed to the rule of law of three important things.

First, the intensity and scope of the Justice Department’s commitment to prosecuting those who invaded the Capitol have been breathtaking. Amidst the focus on the delays in bringing former President Donald Trump to justice, it is easy to overlook that 1,400 people who participated in the Capitol riot have been charged. More than 900 have been convicted, most by guilty plea.

Second, Friday’s sentence is a reminder of the horror of Jan. 6. David Dempsey launched flagpoles, bear spray, riot shields and any other object he could find at police, beating and almost killing at least one. According to the Washington Post, “as fellow rioter Kyle Fitzsimons of Maine yanked at the gas mask of Sgt. Phuson Nguyen, Dempsey fired some spray into the police officer’s face before Fitzsimons snapped the mask shut, trapping the chemicals inside. ‘I thought that’s, you know, where I’m going to die,’ Nguyen testified.”

Finally, and most importantly, Friday’s sentencing reinforces what’s at stake in the coming election. Republicans used to be the party of “law and order,” but Donald Trump is the furthest thing from it.

No one who believes in strong and impartial law enforcement would consider pardoning a man like Dempsey. But Trump has said that if elected, he will consider pardoning or at least commuting the sentences of all of those convicted of crimes that day.

This pledge should not be surprising. After all, Trump himself has been convicted of 34 felonies, putting Republicans’ support for him in stark contrast with any claim to promoting law and order. Perhaps even more relevant, two courts have actually found that Trump incited the Jan. 6 violence. The Supreme Court’s reversal of the Colorado Supreme Court’s ruling did not upend that finding.

In the dystopian world that Trump occupies, it all makes sense. A violence-inciting president who wanted the insurrection to succeed would, of course, like to pardon those who broke the law to keep him in power.

Since Jan. 6, Trump has repeatedly glorified his supporters’ use of force to try to stop the certification of President Biden’s election. Trump has called those who violated the law “unbelievable patriots” and “hostages.” This spring, a Trump campaign rally in Waco, Tex. opened with a video of jailed insurrectionists singing the national anthem — a shameful attempt to whitewash their lawlessness.

That kind of anti-law and order message is hard to put back in the bottle. Criminology research has long established that social disapproval of illegal behavior is necessary to deter crime; approval of it has the opposite effect.

As for pardoning convicted criminals, anyone seriously engaged in law enforcement knows that the likelihood of accountability and consequences contributes both to deterring others and to reducing recidivism. A political leader undermining the consequences of misconduct has the opposite effect.

Those now behind bars for Jan. 6 lawbreaking have heard Trump’s pledge to undo their convictions if he is elected. In June, insurrectionist John Banuelos, accused of firing a gun on Jan. 6, said this to the judge arraigning him: “Trump is going to be in office in six months, so I have nothing to worry about.”

It appears that the “the biggest investigation in the Department of Justice’s history,” as former prosecutor and Rep. Dan Goldman (D-N.Y.) put it, will be for naught if Trump regains the White House. He would undo the message that the Justice Department sent: Participate in violence and we will find you and hold you to account.

With the Biden Justice Department sending that message, violent crime is dramatically down in major cities this year. Under a Harris-Walz administration, led by a career prosecutor, there would be no Jan. 6 pardons.

In contrast, Trump pardons would deeply damage faith in the rule of law. Its erosion leads to citizens asking why they should follow the rules when others get away with near-murder. The road to social discord and security lost is paved with distrust of fair and equal justice.

The framers who wrote our Constitution’s preamble 237 years ago did so to “ensure Domestic Tranquility.” This year, public safety is on the ballot.

Dennis Aftergut is a former federal prosecutor and civil litigator, currently of counsel to Lawyers Defending American Democracy.