I’m going to discuss impeachment, but first I want to talk about the National Symphony Orchestra’s opening concert and gala last Saturday night. It was very revealing.

At mid-concert, the chairman of the Kennedy Center, David M. Rubinstein, came out to greet the audience and the VIPs. He welcomed the different ambassadors, then he went through the Cabinet members present and then the Supreme Court justices. He introduced Justice Samuel Alito, who got a smattering of applause. Then he introduced Justice Ruth Bader Ginsburg, seated in the balcony. First many women in the audience stood up to applaud. And then everyone stood up. And then everyone applauded. And then everyone applauded more. And then some people cheered. And then some whistled. And it went on and on and on.

It was extraordinary. I’ve been to a lot of Kennedy Center concerts, and a few when the president, sitting in his official box, was introduced. But I’ve never witnessed anything like the reception for Justice Ginsburg. And this was not a totally liberal audience. There were many older GOP donors and corporate types there. This was a spontaneous, bipartisan expression of respect for, and longing for, a national leader of integrity and humility — after three years of a president utterly without shame, for whom no ethical red line has been too red to cross.

There is still a civic pulse in this country. Some Americans still support President Donald Trump, but far, far more are exhausted and disgusted by him. And that is why his latest outrage is so dangerous to him. He knows that we know that many Republicans know that he committed an impeachable offense. And it’s all out there now: a whistleblower complaint filed by a CIA officer detailing how Trump dangled military assistance in front of the president of Ukraine if he would do Trump a “favor” and investigate bogus corruption charges against Joe Biden.

I believe that this not only could warrant Trump’s impeachment but that it could be done without plunging the country into “civil war” or guaranteeing Trump’s re-election — provided Democrats keep stressing four things.

First, this charge against Trump began with an independent whistleblower — an intelligence officer, aided by other insiders. Sure, it could turn out that he was a Hillary Clinton fan, which Trump would use to rile up his base, claiming that Democrats were trying to steal his election mandate. But if this turns out to be what it appears — a nonpolitical CIA analyst and other civil servants motivated by their oath to uphold the Constitution in the face of a president who was violating his oath — then Trump and the Republicans will have a problem.

Democrats in Congress need to make sure they say and do nothing that gets in the middle of this framing of the story, which, for now, appears to be accurate: nonpolitical civil servants inside the government acting on conscience against a lawbreaking president acting on political greed and excess.

That so many GOP senators have kept quiet up to now — save for uber-sycophants like Lindsey Graham — suggests that they fear that this framing is accurate and it stinks to them.

Second, there almost surely will be another nonpolitical, high-integrity civil servant who will testify about Trump and his lawyer Rudy Giuliani. That’s Masha Yovanovitch, the former U.S. ambassador to Ukraine, who was abruptly yanked home in May, months before her assignment was up. My State Department friends who know Yovanovitch say she was a widely respected, professional diplomat. She was apparently removed because she was somehow resisting Giuliani’s efforts to enlist the Ukraine government in Trump’s sordid effort to take down Biden.

Again, how eager will Republicans be to defend Giuliani and Trump by trashing a U.S. ambassador — with a stellar record — who was trying to prevent foreign interference in our elections?

Unlike Robert Mueller, who never spoke until it was too late and had his work “interpreted” by Trump’s attorney general, Bill Barr, the whistleblower and his allies and the former ambassador are — and will be — speaking for themselves.

Third, unlike the Mueller investigation, this case is very easy for people to understand: Trump called the new Ukrainian president, who was desperate for U.S. military aid to use against Russian aggression, and made him an offer he couldn’t refuse: guns for Biden.

Finally, I have no doubt that Trump’s base will stick by him. But they are not the important constituency today, because Trump needs more than his base to get reelected. He needs the moderate Republicans, independents and suburban women who came his way in 2016 — but then abandoned him in 2018, enabling the Democrats to retake the House. What will they do in 2020?

I believe that more than a few will be thinking about a question that will hang over all the impeachment testimony about Trump’s actions in Ukraine: If this is how he behaved while constrained by re-election concerns, how will Trump behave if he gets re-elected — despite this wretched behavior — and no longer needs to worry about re-election? America will become a banana republic.

It’s for all these reasons that Democrats have to be so disciplined in how they prosecute this case. They need to have a single spokesman, U.S. Rep. Adam Schiff, and everyone else needs to keep quiet. They need to have professional prosecutors, not uninformed legislators, question witnesses; they need to keep the focus on the nonpolitical witnesses; and they need to have their presidential candidates stay out of this impeachment story and concentrate on their ideas for reviving and reuniting America.

Impeaching Trump right now on the eve of the next presidential election is very inconvenient. But doing the right thing is often inconvenient and unpopular — and doing it precisely when it’s inconvenient often indicates that it’s the right thing to do. But you have to do the right thing for the right reasons the right way.

Democrats should pursue impeachment in the House as if there were no election in 2020. And they should pursue the 2020 election as if there were no impeachment.

And they should do it by letting the nonpolitical whistleblower and the other civil servants take the lead. These humble patriots started this, and it will go only as far as their credibility sustains it. And it’s their credibility that will influence the swing voters that brought Democrats the House in 2018 — those independents, moderate Republicans and suburban women — a few of whom, I suspect, were at the Kennedy Center last Saturday night, giving a standing ovation to Justice Ginsburg.