At the core of the United States of America vs. Donald J. Trump is no less than the viability of the system constructed in that summer in Philadelphia. Can a sitting president spread lies about an election and try to employ his government’s power to overturn the will of the voters without consequence? The question would have been unimaginable just a few years ago, but the Trump case raises the kind of specter more familiar in countries with histories of coups and juntas and dictators…

George Washington established the precedent of voluntarily stepping down after two of those terms, a restraint later incorporated into the Constitution through the 22nd Amendment. John Adams established the precedent of surrendering power after losing an election. Ever since, every defeated president accepted the verdict of the voters and stepped down. As Ronald Reagan once put it, what “we accept as normal is nothing less than a miracle.”

Until Mr. Trump came along. For all of the many, many allegations made against Mr. Trump on all sorts of subjects during his time on the public stage, everything else feels small by comparison. While he failed to keep his grip on power, Mr. Trump has undermined the credibility of elections in the United States by persuading three in 10 Americans that the 2020 election was somehow stolen from him even though there is no evidence of that and many of his own advisers and even some members of his own family do not believe it.