Just over two months ago, hours after a lone gunman opened fire at Republican members of Congress practicing baseball one lovely June morning in suburban Washington, D.C., Sen. Bernie Sanders of Vermont took to the Senate floor to decry the shooting that had wounded four before the would-be assassin was shot dead by Capitol police.

The shooter, James Hodgkinson, had been a volunteer for the senator’s presidential campaign. He was an overheated far-left militant, burning with hatred for Republicans, especially President Donald Trump, and with resentment of the rich. Those political preoccupations may have helped turn his troubled mind toward violence.

Sanders said all the right things that day, “in the strongest possible terms,” as he put it.

Declaring that he was “sickened by this despicable act,” Sanders added that “[v]iolence of any kind is unacceptable in our society. … Real change can only come about through nonviolent action, and anything else runs counter to our most deeply held American values.”

Excellent words. Yet after the past week’s trauma, one thing seems notably absent from Sanders’ well-received remarks back then. The senator said nothing to condemn, or even criticize, the ideology that apparently fueled Hodgkinson’s violent rage. He did not denounce, say, “left-wing radicalism” or “class warfare mentality” or even generic “partisan extremism.”

Instead, in the face of political violence, Sanders drew the bright line that has traditionally defined a sharp boundary between what is “unacceptable in our society” and what lies at the heart of American freedom.

The line is this: Americans are free to think and “speak” as they will, to call and push for whatever “real change” they desire — however much some of their fellow citizens may decry or even abhor their views.

It is violence, on the other hand — “of any kind” — that never can be tolerated.

Donald Trump’s comprehensive deficiencies as president — and the overheated responses they inspire so widely — threaten to undermine many vital principles of American political life.

A week ago, in the wake of political violence in Charlottesville, Va., what might be called “Trump fever” accelerated a troubling trend already far advanced in America. We are moving unnervingly toward forgetting that it is uniquely political violence — assault on the rule of law and peaceful democratic processes — wholly divorced from the various ideological motives that may inspire it, that is the ultimate unAmericanism.

After clashes between white nationalist groups and counterprotesters ended on Aug. 12 in a brutal vehicular murder by a young neo-Nazi, Trump, initially sounding rather like Sanders, decried “in the strongest possible terms” the day’s “egregious display of hatred, bigotry and violence.” But Trump went on to say those evils had arisen “on many sides,” and had been “going on for a long time in our country.” And this attempt to broaden responsibility ignited a firestorm.

In a backlash notable even in the Trump era for its ferocity and lockstep unanimity, the president’s “muted” response was denounced as a “dog-whistle” signaling the racist right that he was still with them.

Trump, ever clumsy and shallow, surely should have focused his remarks more intently on the singular horror of Heather Heyer’s murder.

But overwhelmingly, the charge leveled against him was not that he had failed to decry the Charlottesville violence clearly enough. It was that he didn’t denounce the ideology of those protesting the removal of a Robert E. Lee statue.

What should move the nation toward “moral clarity,” wrote prominent progressive commentator E.J. Dionne of the Washington Post, was “President Trump’s disgraceful refusal to condemn white supremacy, bigotry and Nazism” — his failing to declare that “[r]acism, anti-Semitism, discrimination and white supremacy are unequivocally wrong.” Legions of others said substantially the same thing.

Of course, there’s nothing new about people blasting Trump for abetting white supremacist ideas. And at most times there’s nothing whatever wrong with that criticism — just as there’s nothing wrong with criticizing Bernie Sanders for encouraging class envy, if one is so inclined.

But when actual political violence surfaces, it is crucial that leaders, and all Americans, reaffirm the all-important difference between violence and any other kind of political action.

Another Post pundit, Dana Milbank, seemed to suggest, as many did, that even if there had been some responsibility for clashes on both sides “there is — and there can be — no moral equivalence between Nazis and those who oppose Nazis.”

But Hodgkinson no doubt was an ardent anti-Nazi.

Only by distinguishing clearly between violence and ideas can it be made clear to hotheads of every type that violence “of any kind” is rejected — even by those who share the political passion in whose name it may be committed.

This is the message Sanders rightly delivered in June. And it is the message commentators and politicians usually deliver when demonstrations turn violent or lawless — when, say, racial-justice protesters block freeways or riot. In those cases the basic right of free expression is routinely acknowledged by politicians and pundits alike. One saw few statements of that kind last week where the right-wing protesters in Charlottesville were concerned. (A welcome exception is the week’s end editorial from the St. Louis Post-Dispatch reprinted in the Other Views section.)

To be sure, back in June there was a lot of pious talk about “toning down the rhetoric,” and some of it became an unworthy attempt among some conservatives to blame Hodgkinson’s vile deed on liberal excesses.

And does Trump sympathize with white supremacists? No doubt — especially to the extent that what progressives often call “white supremacists” include everyone who objects to pulling down Confederate monuments, or thinks immigration should be curtailed, and so on.

In the end, if ours were a society that criminalized toxic ideas, racist ideas would be excellent candidates for suppression. But the American theory has always held that no government, no majority, can be trusted with the power to outlaw beliefs and imprison thoughts — that such a power is more dangerous than political theories can ever be.

We can and must, however, suppress political violence “of any kind” and on “many sides.” To do so, we need to keep the difference between violence and ideas straight.

D.J. Tice is at Doug.Tice@startribune.com.