The bipolar days are here, half the planet at its farthest remove from sunlight and warmth, the other half engulfed by fires and some of the hottest days ever recorded.

We live by laws that have no control over the great certainty of the earth: that it spins on a tilted axis, and this week cast one sphere mostly in darkness and the other in light. The great uncertainty, the fragile construct of civilization, had a solstice of sorts in the nation’s capital Wednesday. It was a fine day for the Constitution.

People are capable of doing extraordinary things in the season of inertia and gloom. The Continental Army of 1777 built a winter camp of 12,000 stragglers just 18 miles from British-occupied Philadelphia. Many of the desperate and the cold at Valley Forge would eventually defeat the mightiest empire on earth. Two thousand others would not see the springtime.

Seventy-five years ago this month, an army of kids in thin jackets and shredded boots faced down the last big western thrust of the Nazi war machine in the frozen Ardennes forest. For Americans, the Battle of the Bulge was the bloodiest in the war against the greatest evil of the 20th century.

A handful of the soldiers who survived that carnage, now in their final years, were asked this week at a battleground memorial why they made that sacrifice for others. Their answer was quoted by Speaker Nancy Pelosi as she assumed her role in executing the gravest act a government of the people can take against a tyrannical president.

“We came here to fight for you not because you are Americans,” she said, explaining the why of the soldiers, “but because we are Americans.”

President Donald Trump took a can of spray paint and a hammer to that history. Rather than help a struggling ally, he sought to extort it. He used American taxpayer money as a club to induce a foreign power to intervene in our election, and then obstructed efforts to get at the truth of the betrayal. These facts are not in dispute, which is the only reason Republicans in the Senate refuse to hold a legitimate trial.

As it is, a fog of criminality hangs over all of Trump world. When Rick Gates, the former Trump deputy campaign chairman, was sentenced to jail this week, he became the fourth close associate of the president to be locked up. Two others are awaiting sentencing on serious felonies.

That our president is a monumental cheater — on his wives, on his country, on his charity, on truth, on numerous business contractors, and even his golf game — is also not in dispute. The greater sadness is how the inflammation of Trumpism has spread to people and institutions that were once thought to be immune from his indecency.

Is it just a coincidence that the first team to win a World Series in the inaugural year of Trump’s presidency, the Houston Astros, is now under investigation for systematic cheating?

On impeachment day, a heartless president was true to form. He accepted no responsibility, not even a smidgen, for the actions that will put him on the dark side of Mount Rushmore, the third president to be impeached in the history of the republic. He picked a fight with a widow, Rep. Debbie Dingell, suggesting that her husband of 38 years, the late John Dingell, a World War II Army lieutenant and the longest-serving member of Congress ever, was in hell.

But as I said, the season of darkness presents many opportunities for light-starved souls. Going into the Christmas season a few years ago I got a grim note from Brian Doyle, a gifted storyteller and writer, New York born, Oregonian by choice. He had been diagnosed with a malignant brain tumor, he said. He died a few months later, in the spring of 2017 at the age of 60.

“We’re only here for a minute,” Doyle told another wonderful writer, David James Duncan, in “One Long River of Song: Notes on Wonder,” a new book of Doyle’s essays. “We’re here for a little window. And to use that time to catch and share shards of light and laughter and grace seems to me the great story.”

So we use those shards of light for the great story. At this moment, that means an unstable world, made more so by an unstable president, needed a firm statement of principle. We got it on Wednesday.

But in the meantime there is the Senate, where that contagion of Trumpism has spread to all but a handful of Republicans. If the president had truly done nothing wrong, Senate leaders would call witnesses and air the facts. Instead, they will attack the process and ignore the substance of the high crime at the center of Trump’s impeachment.

And many will follow Sen. Mitch McConnell, swearing an oath to “do impartial justice,” only to violate that oath before proceedings begin.

As usual, Oscar Wilde, my favorite Irish ghost, had it right: “The one duty we owe to history is to rewrite it.” The rewriting, and righting, of the Trump era gets closer now that the days are getting longer.

Timothy Egan

Timothy Egan is an Op-Ed columnist for The New York Times.