Progressive American politicians must embrace the necessity of dramatic action on climate change as a touchstone. So far, Senator Bernie Sanders has done it the most persuasively, campaigning on addressing climate change, health care, racial justice, and economic inequality as his unvaried quartet of issues, invoked in every speech and backed up with serious legislation that shows a willingness to move with real speed. Other party leaders will back him on one bill or another, and scientists and engineers are now running for office. Seriousness on climate change needs to be a qualification, not an afterthought, for anyone who wants to run for president. Because it’s not an environmental issue; it’s the most crucial security question that humans have ever faced.

“Security” in the most basic sense: There is a nontrivial chance that the area where you live, your particular home, is going to face a wildfire or flood or extreme storm or killer heat wave in the years ahead. The insurance industry, the part of our economy that we ask to analyze risk, has been clear about this. But at this point, the real experts are the people who survived last fall’s California firestorms, or Hurricane Maria’s assault on Puerto Rico.

When we talk about “security” in magazines, we usually mean something to do with armies and guns and foreign policy. The Pentagon has actually been the one arm of traditional conservative power in America willing to at least lay out the facts of our climate peril, and ranking officers have become ever more outspoken: In 2013, the head of US forces in the Pacific, Adm. Samuel Locklear III, told a reporter that, although he was in charge of dealing with the threats from North Korea and China, the thing his planners feared most was global warming. It was “probably the most likely thing that is going to happen…that will cripple the security environment, probably more likely than the other scenarios we all often talk about.” Though President Trump has forced even the military to remove most overt references to climate change from its reports, one imagines that military planners aren’t fooled, if for no other reason than that rising sea levels and extreme weather threaten half of US bases and ports, according to one study. But it goes far deeper than that: Instability and chaos are the great enemies of peace, and the invariable outriders of climate change.

Failure looks like Syria, where a deep drought—the worst in the Levant in nearly a millennium—forced a million farmers off their land and into the already unstable cities a decade ago. One study after another now shows that this played a crucial role in helping trigger the conflict there, which in turn helped to fuel the hateful new politics in our own country and Europe. Now multiply that by 100, as rising seas and spreading deserts push more and more people into frightened motion. One of the ironies is that the West fears migration resulting from its own fossil-fuel burning; no one on the Marshall Islands is responsible for, or can stop, the rising sea. It will take our work here to actually ensure that people elsewhere enjoy the right to stay in their own homes.

Success, at this point, looks like… well, not stopping global warming—it’s far too late for that—but rather curbing it short of civilizational destruction. This may or may not be possible—but if we are to have a chance at all, it will require unflagging leadership on at least three fronts.

First, we really could move to run the world on renewables in a matter of decades; indeed, academic studies show that the existing technology could get us 80 percent of the way there at affordable prices by 2030. Engineers and manufacturers in California, Germany, and China have done the planet a great service by decreasing the price of solar panels and wind turbines at a prodigious pace; now they’re becoming the cheapest way to produce power on most of the planet. And that electricity could be used to run our transportation systems too, since the electric drivetrain seems finally to have come of age.

But a natural progression won’t happen fast enough; hence the need for government policy aimed at setting targets and then meeting them, with a mix of subsidies, a price on carbon, government procurement, and all of the other tools at a government’s disposal. Germany has shown part of the path forward, and China and California, too—all are making change at rates that matter, and all are showing the results, in terms of both jobs and savings for consumers. California’s recent declaration that all new homes built in the state must come with solar panels is a perfect piece of practical symbolism: It will save the average homebuyer $40 a month, because sunlight doesn’t actually cost anything.

But the state’s governor, Jerry Brown, is also a reminder that even the most progressive Democrats have so far failed on the second test for real action on climate change: the pressing need to keep fossil fuels in the ground. So far, he’s been unwilling to slow down California’s oil industry, the third-biggest in the nation, even though scientific assessments show that 80 percent or more of current fossil-fuel reserves need to stay beneath the soil to avoid catastrophic warming. That’s why the environmental movement has worked so hard to block new pipelines, new fracking wells, new offshore drilling. But it’s much harder than it should be. Seven years of constant campaigning finally convinced Barack Obama that we could do without the Keystone XL pipeline, but his years in office saw the build-out of enough other fossil-fuel infrastructure that the United States passed Russia and Saudi Arabia as the biggest oil and gas producer on earth. The Keep It in the Ground Act, introduced by Sanders, Senator Jeff Merkley, and others, is the kind of key step that all presidential contenders should line up behind.

The third step is to stem the flow of money to the fossil-fuel industry—and here, campaigners have been able to accomplish a fair amount even without federal help. The vast divestment movement, though, has been buoyed by state and local leaders; when the City of New York announced that it was selling its fossil-fuel stocks from pension funds, it sent a nice jolt into the centers of market power, reminding them that the death spiral for oil and gas is under way. Washington needs to end the subsidies that have long enriched the hydrocarbon industry, and one good way to achieve that is for more candidates to join the more than 500 who have already pledged not to accept a penny from oil, gas, or coal companies. (The Democratic National Committee has vowed to do likewise.)

One problem in this distracted age is that, while climate change is the most important thing happening on our planet, there’s almost never a day when it’s the most dramatic story. So a commitment to climate justice needs to be a central and unvarying part of our message, just like racial or gender justice. (They are, of course, deeply allied—looking at Hurricane Maria’s aftermath, it’s not hard to figure out who bears the brunt of catastrophic storms.)

Another problem is that the whole world needs to be moving on climate change. Of all the actions that Trump has taken during his reckless and infantile months in the White House, none will do longer-lasting damage than his abandonment of the Paris climate accord. It’s not that his decision means the conversion to renewable energy won’t continue—“free” is a hard argument to beat, and solar and wind power will eventually spread around the globe. But the momentum that had begun to build at Paris has been hobbled, and the chances of them spreading fast enough to matter are much reduced. We will power the world of the future with renewable energy, but unless we act with great swiftness, it will be a broken world that we power.

So if and when the United States emerges from the Trump era, and if and when progressive politicians really embrace climate change as a core issue in tandem with race, gender, immigration, and inequality, we will have a chance for something new: an activist government whose task, alongside those of China and Europe, will be to help lead in a very different direction the planet that we’ve done the most to pollute. If there’s any reason for a superpower, it’s got everything to do with… power.