At Wednesday’s Democratic presidential primary debate, Bernie Sanders got an easy question — easy, that is, for a minimally reasonable politician seeking to govern a diverse nation. Sanders gave the wrong answer.

“Chants of ‘lock her up” are still heard at President Trump’s rallies today,” moderator Rachel Maddow noted. “Now some opponents of the president are turning the same slogan against him. They’ve chanted ‘lock him up’ at a recent World Series game in Washington and at a Veterans Day event in New York and, Senator Sanders, at least two of your campaign events recently. Senator, should Democrats discourage this? Or are you okay with it?”

Sanders responded: “Well, I think the people of this country are catching on to the degree that this president thinks he is above the law. And what the American people are saying is: Nobody is above the law.” Then he pivoted to talk about how the country would unite around his agenda.

No. The right answer is: “It is understandable that people are frustrated with President Trump. But everyone else should resist stooping to his level. I wish people would not do Trump-like chants at my rallies.” Instead, Sanders essentially said, “Well, people think the president is a criminal.”

On an evening in which the candidates frequently discussed how the next president might bring the country together after the hyper-divisiveness of the Trump era, it became clearer than ever that Sanders’s big idea is that he will unite America because America will realize it agrees with him, not that he can tap into common beliefs that transcend his narrow ideological program.

Joe Biden stepped in with a better response.

“I don’t think it’s a good idea that we mock — that we model ourselves after Trump and say, ‘Lock him up,’" Biden said. "Look, we have to bring this country together. Let’s start talking civilly to people. Follow the law, let the Justice Department make the judgment as to whether or not someone should be prosecuted, period.”

Biden has been overly optimistic about his ability to strike deals with an extremist Republican Party. But he is right that compromise and civility are the hallmarks of a functioning democracy. Ideologues see these as obstacles. Everyone else should see them as necessities. The next president should at least understand this.

Democrats should not embrace tactics that would alienate the other side as much as Trump has alienated his critics, and defeating Trump should represent a clear victory for the rule of law, not encourage more questions about how tenuous it is in this country.

The implication of “lock her up” and “lock him up” is that the other side is so depraved that even the most essential rules can be bypassed in dealing with them. It can never be the case in America that when the presidency changes hands, the previous administration faces prosecution because the other side’s voters have convinced themselves, reasonably or unreasonably, that the last government was filled with criminals. The stakes of losing an election would become so high that there would be no orderly transfer of power — or, perhaps, no transfer of power at all.

When crowds at Barack Obama’s rallies would boo at the mention of a Republican, Obama would always — always — insist, “don’t boo, vote.” Democrats should remember that, not so long ago, a decent human won the presidency and made many people proud of their own side, rather than simply angry at the other.

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