Before the second impeachment trial of Donald J. Trump began Tuesday, it may have been tempting to think of it as a sequel to a show that had been canceled, a sequel no one needed.

“Not more of him,” I heard someone moan beforehand, in the way I’ve heard people talk about the “Sex and the City” reboot. “Can’t we just move on?”

This person was no Trump fan, just a regular American tired of feeding the former president’s bottomless need for attention and the media’s bottomless need for ratings and clicks. It’s an understandable exhaustion. For years Trump — with his tweets, his threats, his preening, his lies — hijacked our minds, our time, our politics. Enough already.

But any impulse to “just move on” from the insurrection Trump stoked at the United States Capitol on Jan. 6 was surely extinguished Tuesday in the minds of all rational people. It wasn’t the legal arguments over the trial’s constitutionality that made the strongest case for continuing this saga, and it wasn’t the history lessons. The persuasion was in the video. There it was again, that crazy January day, relived on the screens in the U.S. Senate chamber and on screens all over the country.

There was President Trump urging his supporters to march to the Capitol, warning them, “If you don’t fight like hell you’re not gonna have a country anymore.”

There was the giant mob, fueled by a delusion that the presidential election was stolen, kicking down the Capitol barricades, shoving through Capitol doors, shouting vulgarities, threatening police officers they called pigs.

There was the brave officer leading the shouting marauders away from the chamber where senators had assembled to certify the new president.

And there was Trump again, much later, when things had gone so ugly, telling the rioters to go home but assuring them, “We love you. You’re very special.”

“If that’s not an impeachable offense, then there’s no such thing,” Rep. Jamie Raskin, the lead impeachment manager, told the senators when the video ended Tuesday.

To judge from the reaction on social media, and from the way I felt, the video brought the Capitol siege alive as vividly as the day it occurred, maybe more so. The images were startling not only because they reminded us that yes, that really happened. In this country. Just last month. The video shocked also because it reminded us how easily we can be lured into forgetting how awful and dangerous that day was.

As a culture, we have short attention spans, even for what’s terrible. New outrages arrive daily to dislodge the old ones from our minds and conversations. It’s so much easier to move on to arguing about things, like, you know, that Bruce Springsteen Super Bowl ad.

The video snapped us back to reality, to urgency.

Those of us at home Tuesday could only imagine what the senators were feeling as they watched the replay of a riot they had experienced in real life in that same building. Raskin, a Democrat from Maryland, helped us imagine.

He recalled the day of the siege, which happened to be the day after he buried his son, who had taken his life in December. His daughter and son-in-law had joined him at the Capitol, in a show of support, only to wind up hiding under a desk, thinking they were going to die.

Raskin recalled the rioters pounding on the door “like a battering ram.” He choked up remembering how he’d told his daughter they’d come back to the Capitol on a better day; she said she never wanted to come back.

“This,” he said, “cannot be the future of America.”

The future, not the past, is at stake in this trial. It’s not a sequel to a story that’s over. It’s the culminating moment of this strange American saga, in which a president encouraged an assault on our laws and lawmakers. Trump’s presidency won’t be fully over until his behavior and its consequences are fully accounted for in the official government record, until each senator is forced to take a stand.

And let’s remember: This trial isn’t essentially about Donald Trump. It’s about us, who we are and want to be. It’s not primarily about punishing him. It’s about protecting ourselves, our laws, our country.

Mary Schmich is a columnist for the Chicago Tribune and winner of the 2012 Pulitzer Prize for commentary.