No more red energy, blue energy. Geothermal is purple — and Washington is delaying it.

What kind of American are you? Do you shudder at the thought of drilling for oil and gas — or do you cringe at the sight of solar panels and wind turbines?

In recent years, how we keep the lights on has become part of the culture war. For many on the right, loyalty to fossil fuels became a proud way to stick it to the libs. On the left, electric vehicles and rooftop solar became markers of status and moral virtue.

Lay down your culture-war guns. One energy source remains tribeless — and strikingly underappreciated.

Perhaps that’s because geothermal energy has no sex appeal.

Generations of oil-and-gas mythology in American culture evoke independence and sheer national might. Solar panels and wind turbines became emblems of caring for the world. Nuclear has spent decades accumulating its own strange mix of techno-optimism, policy-bro love, and Cold War anxiety.

And there sits geothermal. Who? What? Its PR team should be fired.

Geothermal is exactly what its Greek roots imply: geo, earth; thermal, heat. To turn on the lights, we simply need to harness the heat our planet is already making. And it could save us six ways from Sunday. It’s an unlikely mix of keeping the lights on, muscle-flexing Americana, and tree-hugging peace and love. It sends all the right signals to both red and blue America. It’s perfectly purple.

For the tree-huggers: geothermal produces very little carbon, disturbs comparatively little land, and doesn’t require mountains of fuel to be dug up and burned.

For the drill-baby-drill crowd: geothermal is domestic energy pulled straight from American soil. It’s very much drill, baby, drill — except this time, we’re drilling for the Earth’s heat instead of ancient hydrocarbons. And unlike the blue-coded renewables, it can run day and night regardless of the weather.

The left gets reliable, climate-friendly power. The right gets to drill for American energy dominance. Americans of all stripes get electricity when they need it. Everyone wins.

Or at least that’s the idea. Geothermal provides just 0.4 percent of America’s electricity. Not because the energy isn’t there. Geothermal could supply up to 20 percent of American power by 2050. The Earth is not running out of heat anytime soon. So the real limit is not supply — it’s how cheaply and efficiently we can reach it.

Unsurprisingly, the government makes that a lot harder than it needs to be. The government’s own research says permitting laws add time, cost and risk to geothermal development.

But fear not. There’s a supposed fast lane for low-impact projects on federal land: categorical exclusions, or CXs. Perfect for modest geothermal exploration that’s about as environmentally friendly as it gets, right?

There’s just one problem: the fast lane isn’t very fast. Geothermal exploration projects can spend several months — and sometimes more than a year — waiting for approval just to get started.

That is, approval simply to explore for the right conditions to access geothermal heat. Sometimes companies are asking only to stick small probes in the ground and remove them with virtually no lasting disturbance.

Here’s the kicker: the supposedly slower reviews have deadlines. Environmental assessments generally get one year; Environmental impact statements get two. CXs? No deadline. And new research found that 8 percent of geothermal CXs took more than a year.

You can’t have a geothermal boom if it takes a year to get permission to look for its source. Every month lost to exploration delays the power plant that might follow — and discourages investors and developers from taking the next risk.

Putting a deadline on CXs, as Congress did for the other review types, seems like an easy fix to a farcical problem. Maybe then geothermal can start producing a larger share of America’s electricity — and Americans can discover an energy source they don’t have to fight over.

Embracing geothermal probably won’t end the culture war. But it might get us to stop bickering for a moment about how to turn the lights on — and simply turn the damn lights on.

Tobias Russell is the strategic research manager for the Environment and Natural Resources practice group at Pacific Legal Foundation.