Jason Van Dyke needs to testify. Here’s why.

Officer Jason Van Dyke should take the stand and defend himself against charges that he murdered Laquan McDonald.

He should have to raise his right hand and swear to “tell the truth, the whole truth and nothing but the truth.”

And here’s why.

The Van Dyke trial could either tear this city apart or help bind the wounds inflicted by accusations that the white Chicago cop wrongly shot a black teenager 16 times as the teen was walking away.

We need to hear from Van Dyke why he kept firing even when the teenager lay crumpled on the asphalt.

Because after nearly four years of turmoil over the brutality depicted in the police dash-cam video that captured the shooting, we need to heal.

Yet healing can’t take place until the people — and let us not forget that this trial is “The People v. Jason Van Dyke” — believe the truth has come out.

Only then is it possible there can be reconciliation.

Whatever verdict is rendered in this case, we all will have to live with it.

If, after all of the evidence has been presented, a jury finds that Van Dyke was justified in using deadly force, I am confident the activists who have kept up a drumbeat for justice will express their disappointment without destroying property.

I can’t say the same for instigators who might try to use the outcome of this trial to further their own causes.

There was anger when, in a previous case, a Cook County judge acquitted Dante Servin, a white police officer, of involuntary manslaughter in the shooting death of Rekia Boyd, a 22-year-old black woman. But there was no rioting.

And that seemed like it would be a cut-and-dried conviction. After all, Servin was off-duty when he fatally shot Boyd, firing into a crowd of people walking in a dark alley.

Servin got off when the judge ruled that the Cook County state’s attorney’s office erred by not charging the police officer with the more serious crime of murder.

It was a legality that few people in the ‘hood likely understood.

All they knew was that an off-duty cop fired into a crowd and killed an innocent young woman. To them, the judge’s legal jargon essentially amounted to an “oops.”

But if there is ever to be peace between the police and communities of color, a lot more citizens living in those communities must trust that police are using the same standards of decency they use in predominantly white communities.

The videotape of McDonald’s death symbolized what black people find most offensive about policing in their neighborhoods — that too often police behave as if black lives do not matter.

Although Van Dyke’s former partner, Joseph Walsh, testified under oath that McDonald was “aggressive” and re-enacted McDonald allegedly brandishing a knife, that doesn’t explain why Van Dyke fired 16 times.

The city has been operating under a thick cloud of distrust every since. This police-involved shooting led to the establishment of the Police Accountability Task Force and a comprehensive review that concluded that African-Americans were disproportionately subjected to bias policing.

It also led to a Justice Department civil rights investigation that forced the city into a federal consent decree on police reform.

McDonald’s death at the hands of Van Dyke caused such political upheaval that it swept former State’s Attorney Anita Alvarez out of office and has overshadowed Mayor Rahm Emanuel’s second term.

None of these transformative events would have occurred without the dash-cam video — a graphic video clip capturing the horrifying moments when Van Dyke made the fatal decision to shoot.

Van Dyke’s partner resigned from the police department in 2016. He and two other officers were charged in 2017 with obstruction of justice and conspiracy.

That these white Chicago police officers are accused of covering up for Van Dyke might surprise Chicago’s white residents.

For many black residents, though, it is seen as standard procedure.

While defense attorneys expressed concerns that Van Dyke wouldn’t get a fair trial in Cook County that was a bogus worry.

After all, no Chicago police officer has been convicted of murder in 50 years.

The Van Dyke trial is the most important trial this city has seen since.

Because, if a Chicago cop can shoot someone 16 times under these circumstances, then what chance is there ever of holding a police officer accountable when he or she uses deadly force unjustifiably.

What Van Dyke says after the trial won’t matter.

The city needs to hear the truth — now.

Justice is at stake.