To the Republican members of the United States Senate:

You have always told us that you believe in the distinctive greatness of the United States of America. “America is different,” as Senator Marco Rubio has said. Ben Sasse likes to say that “America is an idea” — a commitment to universal dignity over brute power.

You have also told us that you went into politics to serve a higher purpose. Well, your moment has arrived.

The president of the United States is betraying his oath of office in the most fundamental way, by using the presidency for personal gain at the country’s expense. He has corrupted our foreign policy with grubby attempts to help himself that his own White House staff immediately recognized as improper. He is telling the world that America does not, in fact, stand for any higher ideal. Can you for a moment imagine the icons of your party, like Ronald Reagan or Dwight Eisenhower, risking the security of a country threatened by Russia, for the sake of smearing a political rival?

President Trump must go, and you — only you — have the power to make it happen.

You can start to distance yourself from him slowly, if it will help bring along your political base. A couple of you — like Pat Toomey of Pennsylvania, who called Trump’s behavior “inappropriate,” and Mitt Romney of Utah, who used the word “troubling” — have begun to do so. But more of you should be moving in this direction, for the sake of the country and, ultimately, yourselves.