Elected Republicans are right that President Trump’s impeachment is, in many aspects, a tragedy. It has worsened the distemper of our national life and probably turned the next presidential election into an angry and defensive referendum on the last one. And the removal of Trump by the Senate would — whatever else it accomplished — plant a malignant conspiracy theory at the heart of our politics for a generation.

I do not envy the task of Republican senators, trying to balance the near-unanimity of their party in support of the president and the public responsibilities imposed by a Senate trial. Nothing is easy or obvious about the choice they will make. Voting for the removal of the president, in many places where Republicans predominate, might end a useful career. It does no good to play down or deny that risk.

But eventually, in the silent hours of the night, in the quiet of their consciences, Republican senators will determine what they really believe about the facts of this case, and the duties those facts impose. And I respectfully hope that they — and their Republican constituents — will consider a few arguments before making a final decision.

Most of the circumstances of this case are not seriously disputed. Trump requested the help of Ukraine’s president in uncovering politically damaging material on a political rival and his son. This is confirmed by documentary evidence and direct witnesses. Denying it is not an option for people being honest with themselves.

A request of this sort made by Ukraine’s main source of military assistance during an ongoing conflict was bound to be taken as a demand. It appears that military aid was withheld for a time with the goal of pressuring Ukraine to announce the start of an investigation. And we know that securing Ukraine’s cooperation was the goal of a broader, quasi-diplomatic effort led by the president’s personal lawyer.

It might be argued that squeezing Ukraine to secure political help was wrong but is not impeachable (an argument I oppose but don’t dismiss). Yet that is not what the president is asking. Though Trump obviously did what is alleged, he is requiring his supporters to say he didn’t. The president is not looking for mercy or forgiveness; he is demanding that his followers give evidence of their loyalty by denying reality. Voting to acquit the president would be to say he gets to define his own facts.

Republicans struggling with this considerable request should keep a few points in mind:

The first concerns hypocrisy. What would Republicans be saying about a Democratic president — say, if Hillary Clinton had been elected — who engaged in Trump’s behavior? There is simply no doubt that most would be calling for impeachment and, if they controlled the House, voting for impeachment. I also have no doubt that most elected Democrats, in that circumstance, would rally to their leader, feeling justified by the importance of their broader ideological agenda. Such is the nature of polarization.

But public standards can’t be based on the worst tendencies and practices of both parties. This race to the ethical bottom is beginning to threaten the health and legitimacy of American democracy. Someone has to stop it. And this can be achieved only when people hold their own side to account.

A second point to remember is the moral hazard Trump’s acquittal would create. Does anyone doubt that this would embolden him to engage in more self-dealing, more abuse of his office for private gain, more cynical manipulation of foreign policy for his own interests? His infamous July 25 call with President Volodymyr Zelensky came just days after Trump felt vindicated by former special counsel Robert S. Mueller III’s stumbling congressional testimony. Does anyone question that Trump would regard acquittal as permission for further recklessness?

A final point concerns character. There is a lot of talk about the historical weight of our political moment. But history is generally not made by people pondering their role in history. It is driven upward by men and women who make a difficult moral choice before them, and then the next, in the faith that doing the right thing is never really the wrong move — that what is sacrificed in a good cause is more than balanced by the admiration of people who matter to you, and the peace of knowing your purpose.

Trump’s removal might be the last, best time to redraw some moral lines — between truth and lies, between selfishness and service, between courage and fecklessness — that have nearly been erased in our politics. And all it would take is 20 Republican senators who heed the call of conscience.

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