Forget about gentle phrases like “global warming” (which sounds almost soothing, practically comfy) or even the Republican poll-tested “climate change” (hey, things change, whaddaya gonna do, right?). CNN says tonight’s epic, seven-hour live “town hall” is about the “climate crisis,” with 10 candidates for the Democratic nomination for president talking for 40 minutes each about the existential threat of a planet that’s increasingly on fire or under water. If we’re living in a new geological epoch, an “anthropocene” defined by accidental capitalist geoengineering, well, maybe it makes sense to broadcast what’ll seem like a full eon of television to talk it out.

In a broad sense, all ten of those candidates believe pretty much the same thing: Human industry emits carbon dioxide and other greenhouse gases into the atmosphere, which retain heat, changing the planetary ecosystem in ways detrimental to human civilization and the environment. This is where we’re at.

But now those people have to come up with a policy response to that scientific and technical problem, and figure out a way to explain it to voters. (This town hall seems to have spurred a bunch of them to release specific plans in advance.) These candidates are trying to find policies—to address climate and everything else—that’ll convince Democratic voters to give them the nomination but also show up at the polls in 2020. It’s a needle-thread between the climate activists who’ve forced this issue to the fore and the non-voters, undecideds, and swing voters. That’s a minefield in a thicket, socked in by fog.

So as you watch all seven hours of the Town Hall tonight, as I’m sure you will, look for the ways candidates talk about the policy course they plan to follow, not just because it’s important for, like, saving the planet and stuff, but also because it’ll provide a clue to what election strategy they hope to pursue. Democratic voters already believe climate change is real, human caused, and a threat. Even moderate Republicans believe all that. How a candidate tries to convert that belief to votes, though, is a tell.

For example, would they rather push for a carbon tax or a cap-and-trade program (as the progressive group Data for Progress has characterized the question), or something that might seem more punitive to fossil fuel companies, limiting how much oil and natural gas they extract? Elizabeth Warren announced yesterday that she’d adopt much of the climate plan of former Washington governor Jay Inslee, a candidate for the nomination who dropped out in August. Inslee tried and failed to get a tax on carbon passed in Washington twice; he wanted to phase out oil and gas production in the US altogether and Warren seems to want to break up the companies that do it. These are the kinds of aggressive postures Democrats can take if they don’t accept donations from fossil fuel companies as Donald Trump does, though according to The Washington Post Joe Biden, Pete Buttigieg, Kamala Harris, and Beto O’Rourke have all broken that blanket policy, at least a little.

What’ll be more interesting, though, is how the candidates talk about the consequences of their energy policies. A so-called energy transition to things like solar and wind could well have catastrophic effects on the extractive and manufacturing industries … before other sectors replace them. Some of those industries are unionized, traditionally a Democratic base of support. So the question will be how candidates address that transition, if they do at all. A moderate strategy that hopes to build a strong relationship with unions—and their money and get-out-the-vote machinery—will slow-play the transition, to reach out to the white working class that (depending on whose analysis you read) shifted to Trump in 2016. This is something to watch for from Biden especially, who has tried to stake out a middle-ground, bipartisan approach to climate legislation.

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A more aggressive position might focus on how climate change hurts poor people and people of color disproportionately. Cory Booker and O’Rourke have both made race and racism central to their campaigns. They’re also both polling in the low single digits, and they’re slated to speak late in the Town Hall, toward midnight. That gives their appearances a make-or-break, nothing-to-lose sort of vibe. The move here is environmental justice, pointing out that racist and economically biased policies have put certain kinds of people in harm’s way as climate change exacerbates environmental dangers. It’s a little bit of a bank shot; this morning Kamala Harris tweeted that her climate plan would ensure places like lead-poisoned Flint “aren’t left behind in our fight to stop climate change,” but not every environmental disaster is climate-driven. Still, though, connecting climate to increased inequality would fit a potential larger line of attack on President Trump, who has made racist comments and supported racist policies on immigration and housing, among others. Tactically, this would also be an appeal to another wing of the Democratic base—urban, diverse, and young.