The 2020s opened with dual crises.

In Australia, unprecedented bushfires tore across a total area the size of Virginia, killing at least twenty-nine people and an estimated 1 billion animals, and destroying 2,000 homes. The news was flooded with images of thousands of people taking refuge on Australia’s southeastern coastline, the sun blocked by thick smoke, children wearing surgical masks, in a crisis whose severity is unambiguously tied to climate change.

On January 3, the Trump administration brought the United States to the brink of war when it assassinated Major General Qassem Soleimani, the commander of Iran’s Quds Force and a ranking official of Iran. Iran responded by bombing a US base in Iraq, and the world watched in horror to see what President Trump would do next. Though Trump has backed away from direct warfare for the moment, he vowed on January 8 to escalate already devastating sanctions on Iran.

For those of us who went into the new year sober about the fact that this decade is our chance to stem climate change, the very real possibility of all-out war with Iran was a rude awakening to the fact that US belligerence could ruin everything.

To win a Green New Deal with the teeth to keep fossil fuels in the ground and secure a just transition and job guarantee for all workers, it will take organizing and protest on an unprecedented scale. US wars, however, have historically been used to beat back and repress exactly the kind of Left movements that we need to tackle the climate crisis. The supposed need to protect national unity and “security” during wartime has been used by the US government to justify heightened surveillance and clamp down against those deemed disruptive — disproportionately targeting the Left. World War I was used to justify the passage of the Espionage Act, which criminalized speech deemed “disloyal” and was a bludgeon against anti-war movements, and was also used to prosecute and imprison hundreds of radical unionists. The Cold War, too, was used to justify a vicious campaign of political repression not only against people perceived to be communists and socialists, but also against civil rights and black freedom organizers.

In the aftermath of September 11, 2001, the drumbeat for war in Afghanistan and then Iraq was used to justify a broad range of repressive measures targeting social movements. Democrats overwhelmingly voted for the PATRIOT Act, which gave law enforcement and intelligence agencies sweeping powers to search and surveil World Trade Organization protesters and environmental activists. In November of 2003, Miami police chief John Timoney launched a vicious crackdown on thousands of people who had gathered to protest the Free Trade Area of the Americas Summit: he was assisted by forty law enforcement agencies, the FBI, and $8.5 million earmarked from Congress to pay for the Iraq War, and he had worked hard to convince residents of Miami that protesters were a public safety threat. A crowd of farmworkers, union members, and activists concerned about “free trade” running roughshod over human and planetary well-being was attacked with tear gas, stun guns, rubber bullets, and concussion grenades, as helicopters hovered continuously overhead.

As social movements are besieged, wars are used to justify more militarism across the globe. The United States emerged as the world’s preeminent military empire after World War II, and it has since expanded its empire, now the largest in human history, with 800 bases spanning the globe. If history is any indicator, a US war in Iran would almost certainly lead to a hike in overall military budgets. In fact, the United States has already used its aggression toward Iran to justify increasing the US military presence in the Middle East by 20,000 troops since last spring.

This military empire, in turn, enables the same global bullying driving the climate crisis. The United States is the number-one per-capita emitter of greenhouse gases, while China is the overall highest emitter. Yet its international domination ensures that the United States never has to pay meaningful reparations or answer to those countries hit hardest, most of them in the Global South and still scarred by their histories of colonialism and plunder. And due to its position as the most powerful country in the world, the United States has also dominated the very institutions meant to intervene in global crises — in particular, the United Nations — meaning the United States will never have to answer for its staggering global wrongdoings, from pulling out of the Paris climate accords to waging war in Yemen. The United States wouldn’t have the power that it has if not for its military strength, and if that strength were to diminish, so would its sway at the UN.

There are plenty of reasons for US climate justice and anti-war movements to unite against common enemies. The same Democratic Party leadership that has failed to take robust action to curb climate change and gotten behind Trump’s climate-unfriendly US-Mexico-Canada trade agreement has also reliably rubber-stamped Trump’s massive military budgets and overwhelmingly voted to pass new sanctions on Iran, Russia, and North Korea in 2017. Senator Dianne Feinstein, who last year famously scolded children who asked her to support the Green New Deal by telling them “I know what I’m doing,” also voted to authorize the Iraq War. And Representative Nancy Pelosi, who has been prominently targeted by Sunrise Movement sit-ins, has supported disastrous US interventions from Afghanistan to Libya, and declined to meet with Yemeni peace campaigners. The imperialist arrogance that undergirds the bipartisan war consensus — that the United States has the right to impose its will on the world — also underlies the political consensus that the United States does not need to fulfill its own obligation to reduce the climate harm it is perpetrating across the planet.

Meanwhile, the same fossil fuel companies destroying the planet are donating to powerful think tanks pushing for war. The need for “energy security” — i.e., reliable access to energy sources — has become a popular oil industry buzzword. The notoriously hawkish American Enterprise Institute and Center for Strategic and International Studies receive significant funding from the fossil fuel industry. The Center for American Progress, which pushes militaristic policies in the Democratic Party, also receives funding from the natural gas distributor Pacific Gas and Electric Company. Together, these think tanks have played a role in pushing the United States into the kind of reckless brinkmanship toward Iran that this decade opened with.

There are obviously other sizable militaries in the world other than the United States: as of 2018, China and Russia, for example, had military budgets that were roughly 38.5 percent and 9.4 percent of the US military budget, respectively. But there’s only one that Americans can directly curb and one whose global reach fuels others to keep pace. For the sake of humanity’s future, permanent US war footing cannot continue. If climate change is the cudgel, US empire is the arm that wields it. Our only choice is to stop them both.