Barack Obama and Donald J. Trump are giving Americans a fascinating civics lesson.

A bitter, divisive, ruthless and occasionally slanderous presidential has come to an end. The president is about two months out from the end of his two terms in office. The president-elect — one of the principals in the aforementioned campaign — is about to take the reins of the only public office he’s ever sought.

The two men met for 90 minutes in the Oval Office on Thursday.

They sat before the media and spoke of the transition that has begun. No outward sign of the acrimony that punctuated this campaign. No apparent hard feelings over the amazingly nasty things these men said about each other.

As Trump noted, they had never met face to face — until Thursday.

Now, to be sure, the backdrop isn’t entirely peaceful. Demonstrators have been marching in major-city streets for the past few days protesting Trump’s election. They vow to keep it up. Nor will the outward peacefulness at the White House dissuade others from making angry statements about the winner of this campaign, or about the candidate who lost, Hillary Rodham Clinton.

That shouldn’t cast too large or too dark a pall over the formalities that are occurring at and/or near the center of power.

The president is vowing a smooth transition; indeed, he wants to model the hand-off he got from President Bush and his team in 2009.

The peaceful transition of power is a marvelous aspect of our system of government. It becomes especially noteworthy when the presidents are of differing political parties.

In this particular instance, the transition should become a virtual miracle given the fiery rhetoric that was exchanged over the course of the past 18 months. Indeed, in the case of Trump, he’s been at the forefront of one of the biggest political lies of the past century: the one that suggested that President Obama wasn’t a legitimate American citizen.

None of us knows what the men said to each other in private. I would love to know how that conversation went.

However, we’re entitled to hear what they say in public. I am going to retain my faith that the tradition of peaceful political transition at the highest level of power in the United States will continue.

It’s all part of what enables the United States of America to remain the greatest nation on Earth.