Representative Alexandria Ocasio-Cortez and Senator Ed Markey at a news conference announcing Green New Deal legislation on Thursday. Photo: Bloomberg/Bloomberg via Getty Images

Finally, we have a serious American response to the existential threat of climate change. It is, which should shame us to say, the country’s first.

The Green New Deal is not perfect. It is, as my colleague Jonathan Chait points out, a resolution rather than a bill, which means it’s effectively a statement of principles rather than a genuine plan. And, if you judge it as a plan, indeed it fails: You could not save the planet, or even cut American carbon emissions, simply by passing the Green New Deal into law.

The resolution does not pretend otherwise. It does not allocate money, which means it raises difficult questions about just where the money would come from and how much would be needed. As a functional position paper it glides over some very important questions: about nuclear power and forestry and agriculture and negative emissions, to name a few. These need sorting out. It combines two goals — rapid decarbonization and a rebalancing of American wealth and opportunity — that would be each, on their own, an almost overwhelmingly ambitious project for any Congress to manage, even one that wasn’t fighting a Senate and a White House in the hands of the opposition. These goals have some overlap, since massive infrastructure spending and investment could be channeled in ways that reduce inequality (or not). But they are also two goals that could get in the way of each other — some investments will create more jobs, others reduce the carbon footprint more — and which may not be shared by the same voters, or analysts. Very shortly after the announcement on Thursday, Bloomberg’s Noah Smith tweeted a perspective that may come to dominate the center-left response: “the ‘green’ parts of the Green New Deal are good, the ‘New Deal’ parts are probably disastrously bad.” And, despite the aggressive ambition of the proposal’s goals, it is also, as I wrote earlier this week, inadequate to the problem of climate change (because the U.S. is a less consequential driver of future change than most Americans tend to think).

But even in this larval stage, it’s clear that the Green New Deal is an enormous leap forward — fundamentally, even categorically, more serious than the previous approaches to address the unprecedented threat to human civilization as we now know it. This is because, even as a statement of principle, it leads with the science — placing front and center the eye-catching, horrifying recent findings of the U.N.’s IPCC report. This may sound conventional, but it is a dramatic break from climate policy-making that long defined itself by what was politically possible rather than what was necessary. This alone amounts to a dramatic advance for American climate policy: putting the science first.

The science says that what is necessary to avert catastrophic climate change is truly jaw-dropping: halving emissions by 2030 and completely zeroing out on carbon by 2050, a project that the U.N. says (in language the Green New Deal embraces) would require a mobilization like the one during World War II. But when what is necessary does not seem plausible, where does that leave politics? As my other colleague Eric Levitz suggests, it leaves us with a choice, between accepting the politics of the possible or trying to forge a new politics. That sounds grand, and possibly self-serving for the left wing of the party. But it’s actually a lesson the party as a whole has been learning already — Medicare for All, free college, abolishing ICE. None of these propositions, should they become law, are likely to match their banner rhetoric to a T. But in the aftermath of Obamacare — and its post-passage struggles — the party has seemed to recognize that selling hard with hyperbole and backfilling with policy was okay. In fact, it’s the course of politics. And if hyperbole is okay for health care and higher education and immigration, why shouldn’t it be for climate change? After all, when it comes to climate change, hyperbole isn’t even hyperbole; the science itself is hysterical. Politics is just beginning to catch up.

How feasible is climate action on this scale? At the moment, unfortunately, not very — though it is pretty incredible just how quickly a legislative project of this ambition has acquired the momentum of this: 60 House members and nine senators co-sponsoring, including at least three major Democratic presidential candidates. But as The New Yorker’s Osita Nwanevu points out, while the bill’s lead author in the Senate, Ed Markey, insists he hopes it can pass through the threat of a filibuster with Republican votes, anyone who is even passingly familiar with today’s Republican Party knows that isn’t happening any time soon.

It may not take that long for some Republican legislators to warm to climate action — recent polls show 73 percent of Americans believe climate change is already happening, and almost 70 percent say they are concerned about it. Those numbers have jumped 10 percent and 20 percent, respectively, since just 2015. One can imagine, in a few years, the views of Republicans in Congress will reflect them — at least somewhat. Unfortunately, we simply don’t have the time to wait for the party to come around, as their voters are already beginning to: Halving emissions by 2030 means getting started immediately, on the scale that Ocasio-Cortez and Markey propose. This urgency mocks the filibuster and the 60-vote threshold it establishes. It is why we are already seeing a new groundswell of civil disobedience — like the Minnesota “valve turners” trying to shut down oil pipelines running through the state — and will surely see more in the years to come. Politically, it means that we probably don’t have time to accumulate 60 votes.

It is also why it is so striking that, on Wednesday, House Leader Nancy Pelosi very casually mocked the climate plan, in a conversation with Politico, calling the proposal, “The green dream, or whatever they call it, nobody knows what it is, but they’re for it, right?” For a long time, Americans were told that climate change was a technological challenge, or a problem for markets, or of individual choices about what to eat and what to drive. It isn’t. All the tools to take action are there. Which makes it a political problem, and which is why the failure of American politicians — even the liberal ones, even the heroic ones — to really take seriously the science, even as they name-call the other side for failing to, is so aggravating. Future generations will use less kind words.

On Thursday, Ocasio-Cortez responded to Pelosi. “No, I think it is a green dream,” Ocasio-Cortez said. “I think that all great American programs, everything from the Great Society to the New Deal, started with a vision for our future, and I don’t consider that to be a dismissive term. I think it’s a great term.”

There are legitimate questions about next steps for the Green New Deal. But this sounds like one politician who wants to see action on climate, and who is swallowing pride and seeing advantage wherever she can; and one who is just … not that interested in taking the problem seriously. On Twitter, Grist’s Eric Holthaus called Pelosi a “climate denier,” which I think goes too far, factually. But she is certainly not showing herself to be a climate leader; as the New Republic’s Emily Atkin put it, “Nancy Pelosi has officially redirected the ‘fuck you clap’ toward @AOC.” But when you’re staring down a threat of this size, is it more responsible to roll your eyes at ambition, or take your cues from the science, which says that what is necessary — a global-war-like mobilization — is well outside the bounds of everyday American politics?

Alexandria Ocasio-Cortez has been called a lot of things since she got to Washington, diminished and infantilized in a number of unforgivable ways. Yesterday, she out-grown-up-ed the 78-year-old Speaker of the House.