Do you worry that there are too many people in prison? You should. Do you want to end mass incarceration and curtail abusive policing tactics? Yes, please. Let’s do all that. But we won’t achieve any of it unless we remember two key things:

That’s the lesson of the recall vote that this past week sent San Francisco’s progressive District Attorney Chesa Boudin packing. Even in an ultra-liberal city such as San Francisco, it turns out, safe, clean and quiet streets are a prerequisite for any really ambitious reforms.

The progressive prosecutor movement grew out of a moment when it was possible to forget that, or at least pay it little mind. The United States was comfortably nestled in the trough of a decades-long decline in reported crime, so reform-minded prosecutors were free to focus on allaying the cruelty that our justice system inflicts upon those accused of crimes.

Those prosecutors were right that the criminal justice system is too often a vicious, inhumane mess. But — say it with me now! — crime matters a lot to voters, and when it increases, the political support for leniency is apt to evaporate. So while we should be looking for ways to make the system less draconian, with crime rising everywhere, we need to make sure we find ones that don’t make crime more likely. Like, say, declining to prosecute crimes that you’ve deemed inconsequential but that voters won’t.

Progressives talk a lot about addressing the root causes of crime, but they forgot that one of the most important is human nature. We are selfish and greedy beings, and if crime is rewarding, or disorder tolerated, some people will engage in antisocial behaviors even if all their material needs are met. It is the job of the criminal justice system to deter that.

Unfortunately, the hardest-to-deter people are often those from disadvantaged backgrounds and neighborhoods, in part because they have less to lose from getting caught. Progressives are understandably reluctant to hurt those folks. But of course, the victims of their crimes are disproportionately other disadvantaged people. For that matter, these offenders are often their own worst victims: A life of crime isn’t something to wish for anyone.

But if progressives are wrong about the problem, conservatives are wrong about the solution; too often, they try to deter crime through ever-harsher punishment. Yet crime and public disorder are generally the product of people who have poor impulse control and short time horizons, often because of underlying mental illness or substance abuse problems.

For them, a 1-in-1,000 chance of a five-year prison term doesn’t necessarily offer much more deterrence than a 1-in-1,000 chance of a one-year term — and a 50 percent chance of one night in jail, or a month under house arrest, might well be more effective than either of the more severe, but less likely, punishments. This suggests a potential platform for the Democratic Party that combines compassion for victims with mercy for offenders: ease the severity of punishment, but increase its likelihood.

What would that mean in practice?

Instead of defunding the police, re-fund the police, putting more cops on the beat and improving training. Instead of refusing to prosecute low-level property crimes, add prosecutors and courts so that those crimes can be adjudicated immediately, and light but swift punishment dispensed. Build robust alternatives to incarceration — treatment diversion, intensive probation, house arrest — but understand that those programs often get more effective when judges have the power to dispense a couple of nights in jail when offenders violate the conditions of their release. Provide more treatment beds for substance abusers and the mentally ill, but make it clear that camping on public sidewalks is not a viable alternative to getting clean or taking antipsychotics.

Most important, don’t try to convince voters that the crime and disorder around them represent some kind of romantic rebellion against an unjust system, or simply an unavoidable price of living in a city. Cities can be crowded without being squalid, as New York proved for years. And it is not justice to ask people who work and pay their taxes to tolerate their streets being used as bathrooms and drug markets, their property being stolen or destroyed, their persons being threatened.

Instead, try arguing that crime is a scourge for which individual people are responsible — not just “the system.” But note that the people responsible for those offenses against public order are human beings who sometimes make mistakes, like all human beings do. And finally, outline your plan to build a humane but effective system that will firmly discourage them from making such mistakes again.