I was in the room when Donald Trump announced his plan to ban Muslims from the United States. Speaking at a rally aboard an aircraft carrier outside Charleston, SC on December 7th, 2015, Trump insisted on reading his press release aloud:

Donald J. Trump is calling for a total and complete shutdown of Muslims entering the United States until our country’s representatives can figure out what the hell is going on. We have no choice. We have no choice. We have no choice.”

I was among the almost entirely white crowd when Trump read these words; people who looked like my neighbors, friends, and family. At first, the crowd didn’t know how to react to Trump’s radical announcement. They snuck furtive looks at each other, trying to decide if this was a joke or for real.

Meanwhile, Trump plowed ahead, employing the same sweeping xenophobia he had used to condemn Mexicans as “rapists” and “criminals.” He told us that Muslims “have no sense of reason or respect for human life.” He dropped buzzwords like “sharia” and “jihad.” In a few sentences, Trump managed to convince this largely white crowd that the world’s 1.5 billion Muslims were “coming for all of us.” Immediately after the rally, six of the eight attendees interviewed by CNN said they were in favor of the ban. Three months later, 75% of South Carolina’s Republican voters said they supported banning Muslims as they exited the primary polls, having delivered the state to Trump.

Attending that hateful rally in South Carolina was one of the most depressing experiences of my political life; it hurt me deeply to see people giving into their worst inclinations and prejudices. But the horror show didn’t stop in South Carolina. Since then, Trump has played to the fears and hatreds of a national audience that is essentially a bigger version of that white crowd I stood among last December. From border walls, to “deportation squads,” to retweeting white supremacists, Donald has actively stoked and courted white racism on his way to becoming the leader of the Republican Party. And he’s counting on white people turning out in big numbers to sweep him to the presidency.

The outcome of this election hinges on race. In swing states like Ohio and Pennsylvania, Trump is garnering literally no support among black voters, and he isn’t doing much better with other voters of color. He doesn’t much care. Trump’s strategy relies entirely on energizing white voters, especially older voters and men, to come out in record numbers to support his candidacy. He could win this way. Romney garnered 62% of the white male vote in 2012 and lost; Trump needs to gather somewhere between 67% and 70% to win. This is not as impossible as we might like to think in an election this unpredictable. (For more on this, check out this nifty NPR tool, which allows you to predict the winner using race as the key demographic indicator).

Whether or not Trump wins, the fact that he could get this far through appeals to white racism is terrifying. Let’s be clear: a Trump presidency would be such a catastrophe that it approaches the realm of literal unthinkability. He’s a climate denier who would abolish the EPA. He’d conduct raids and deport 11 million immigrants, breaking up families. He has utter contempt for freedom of speech and of press. He’d ban 1.5 billion Muslims from entering the country. And on and on.

There are many lessons to draw from all this, but here’s a key one for the climate movement and progressives generally: we have a problem with white racism in this country. Granted, this isn’t a news flash; communities of color have always known this. Our opposition knows this too, because they’ve been using it for generations to win political power. Many politicians have gained office using the twin engines of racist rhetoric and corporate donations. It ain’t just money in politics, it’s money and racism in politics. The fossil fuel industry happily cozies up with politicians who use racism as a primary lever to win white votes. Racism is as key an ingredient in climate inaction as is fossil fuel money.

For too long, many environmental organizations have practiced an advocacy that doesn’t acknowledge the nurturance and manipulation of white racism as a taproot of our opposition’s political power. As a climate movement, we have both a moral and a strategic imperative to combat and neutralize the fear, hatred, racism, and xenophobia present in the white electorate. As climate activists, we need to be explicit about the ways in which combating white racism is aligned with our values and vision for climate justice. At the same time, we need to incorporate an anti-racist strategy into our organizing, campaigning, and alliance-building if we want to win on climate, or anything else.

This isn’t going to be easy, and we shouldn’t pretend like racism is the only ingredient in this toxic political brew. But it is a key ingredient, and we’ll need to get smart about eliminating it. It’s going to take a generation of work, hard conversation, and careful listening. We’ll need to get better about communicating a shared vision that works for everyone, white folks and people of color alike. And there are reasons to be hopeful about our ability to bring about a new politics that can put us on this path.

We are taking steps toward a movement that thinks and acts on this analysis. Today, members of 350 Action will join with allies in the environmental, economic, and immigration justice movements to protest the racist politics of Donald Trump, the Republican party, and the corporations that profit from hate. We’re also joining in the #FreedomNow, a national day of action organized the Movement for Black Lives to affirm the right of black people to live freely and fully, without fear of violence and oppression. I hope you’ll join in, and bring a friend or two.

To find a #StopTrump action near you, click here.

To find a #FreedomNow action near you, click here.

Todd Zimmer lives in North Carolina, where he was raised. He works as 350 Action’s National Political Field Organizer.