“Punch More Nazis.” So reads a T-shirt made and proudly worn, as reported in The Post, by an attendee of the recent Netroots Nation conference at which Sen. Elizabeth Warren (D-Mass.) presented her political vision. To some, this seems like a necessary response to the violence emerging from growing white-supremacy movements. It’s the wrong answer. We need to restore a comprehensively shared commitment to nonviolence and clearly repudiate political violence of any kind.

The death of Heather Heyer in Charlottesville, tear gas in the streets of Phoenix, armed individuals now a routine presence at political rallies. Do we need any more signs that our country needs de-escalation? Surely not.

Clear-eyed, honest political leaders on the left, whether Democrats, progressives or left-leaning independents, must confront not only the growth of anarchist and anti-fascist groups but also what seems to be a creeping acceptance, within the broad, diverse world of their political allies, of a commitment to low-grade violence as a political tool.

Clear-eyed, honest political leaders on the right, whether sitting politicians, NeverTrumpers or right-leaning independents, must confront not only the growth of white supremacy and its attendant violence but also the growing acceptance within their ranks of a militia-style approach to politics. Guns at rallies and protests convey a threat, despite claims about plans to protect.

Whatever their political orientation, leaders in civil society — whether clergy, or the heads of associations, or heads of schools and colleges — should likewise step up to advocate a recommitment to the principles of nonviolence. This is not a matter of partisan politics but of preserving the basic foundations of a stable, peaceful society.

White supremacy, anti-Semitism and racism are false gods, ideologies to be repudiated. They must be countered and fought. We must separate the violence that flows from those ideologies from the ideas that animate them. Different tools are at hand for fighting each.

We need to counter extremism’s violence not with punches but with the tools of law and justice. Where hate crimes and acts of domestic terrorism are perpetrated, our judicial institutions must respond. We as citizens must make sure institutions do their jobs, not plan to take the law into our own hands.

When the legitimacy of legal and judicial institutions has come into question — as has occurred because of police shootings and mass incarceration — we must strenuously advance the project of reforming those institutions to achieve their full legitimacy. But to take the law into one’s own hands is only to further undermine legal and judicial institutions. It provides no foundation for reform.

As to extremism’s ideologies, these we need to counter with principles of nonviolence and with a vision for a country in which no one feels endangered on account of their social identity. This is a vision, with a set of supporting policies, for a multiethnic democracy where political equality, social equality and economies that empower all have been achieved. You can’t fight for such ideas, for a society’s very soul, with your fists. We fight for this vision at the ballot box at every level of society — city council, county government, state governments, federal government.

Why nonviolence? Why political process? The purpose of building states, legal systems and democracies is to minimize the use of force for deciding human conflict so that, from conditions of peace, human well-being can emerge.

To choose not to minimize but to increase political violence is to choose to walk away from the only human invention — legitimate, peaceful political process — that has ever held the prospect of bringing safety and happiness for all. To choose political violence is to choose to disassemble the foundation of a just, stable and peaceful society.

Some people think that the ends justify the means, but this is false. To believe this is to put oneself in the position of a dog chasing its tail. You can never get there from here — never reach justice by setting your face toward injustice. Worse still, to accept or to fail to repudiate political violence, supposedly in pursuit of justice, is like trying to climb a mountain by walking steadily downward. Once political violence activates, shutting it off is exceptionally difficult.

Why should anyone believe that people who have been committed to political violence will change their minds and recommit to peaceful forms of litigating conflicts? That kind of distrust erodes the foundations of stable political institutions. The path to justice always lies through justice, including the basic moral idea that immediate self-defense is the only justification for the use of force. We need moral clarity on this point.

To anyone who holds a leadership position: It is time not only to repudiate ideologies of white supremacy but also to step up and make the case for fighting fair within the bounds of political process, leaving guns and fists at home, and forswearing political violence of any kind.