We Americans live in faith with our Constitution and with the past generations of Americans who swore to protect it and fought to defend it. One week from today, we will decide whether Donald Trump is fit to be President of the United States again. He is not. When we entrusted our Constitution and our democracy with him before, he betrayed us. Campaigning for the presidency again, he now promises to exact vengeance against his fellow Americans whom he deems “the enemy from within,” those who have dared to challenge his betrayal, an enemies list that includes Republicans and Democrats alike.

There could be no higher duty of American citizenship than to decisively repudiate a man who betrayed the nation when he was previously entrusted with the highest office in the land and now threatens the persecution of American citizens who have crossed him. In the almost 250 years since the founding of the nation, no president before Donald Trump has ever so betrayed America.

This is not a difficult decision for voters, though my fellow Republicans and conservatives will finally have to decide what they have long hoped they would never have to decide — whether to put their country above their party. Republicans and conservatives have always proudly claimed they would be the first to put the country above all else when the time came. That time has come. If Republicans are unwilling to put America before their party now, they will never do so. They must be honest with themselves.

All Americans, but especially Republicans, will live with their decision the rest of their lives. This election is anything but politics as usual, no matter how desperately Donald Trump and the G.O.P. have tried to make it that.

As a lawyer and a judge, I have devoted my entire life to America’s democracy, Constitution and rule of law. I took solemn oaths to preserve, protect and defend the Constitution against all enemies, foreign as well as domestic. While most Americans do not literally take oaths to preserve and defend the Constitution, all Americans freely assume those same oaths and they should take their obligations seriously every single day of their lives without any reservation. The reason America is still the envy of the world after almost two and a half centuries is because so many of its citizens do take seriously their obligations as citizens.

The powers of the presidency are vast and its responsibilities commensurately immense. It is for those reasons that a president has no higher obligations than to America’s democracy, Constitution and rule of law, the foundational cornerstones of our republic. Through his words and deeds, Donald Trump has over and again demonstrated his palpable contempt for those cornerstones of America’s grand experiment in democratic self-government. He has proved himself to be an anti-democratic, anti-Constitution candidate for the presidency of the United States.