President Trump has done what he promised: kneecapping America's efforts to fight climate change. In a sweeping executive order Tuesday, the president rolled back rules limiting carbon emissions and regulating fossil fuel producers.

Trump explained this dramatic shift in economic terms, saying that he wants to put coal miners back to work and make manufacturing cheaper. His critics suggest financial motives, too, albeit more nefarious ones: that he's interested in little more than lining the pockets of his rich friends in the oil and gas industry.

Really, though, Trump's policy reflects a deeper truth. Climate change denial is not incidental to a nationalist, populist agenda. It's central to it. And that's not a coincidence.

Combating global warming requires international cooperation, multinational agreements and rules. Done right, no country is exceptional, and some might have to sacrifice for others. In other words, it strengthens the international order that Trump and his team are so assiduously trying to dismantle in the name of “America First.”

As Andrew Norton, director of the International Institute for Environment and Development, explains:

“Climate change is a highly inconvenient truth for nationalism, as it is unsolvable at the national level and requires collective action between states and between different national and local communities. Populist nationalism therefore tends to reject the science of climate change however strong the evidence.”

That reality is reflected in populist platforms around the world. In France, for example, the far-right National Front traffics in climate change skepticism. They've rolled out a “patriotic” environmentalist platform that opposes international climate talks as a “communist project. “We don’t want a global agreement or global rule for the environment,” the party's Mireille d’Ornano told the Guardian.

In the past, the National Front has tied environmentalism to xenophobia even more explicitly, protesting the cruelty to animals in the preparation of halal and kosher meat specifically. In other countries, far right “environmentalists” have used ecological conservation to argue that immigration must be strictly capped.

As candidate and president, Trump has explicitly suggested that fighting climate change is at odds with nationalist priorities. In 2012, he tweeted, “the concept of global warming was created by and for the Chinese to make U.S. manufacturing noncompetitive.” In 2016, he promised to pull out of the Paris and stop cut U.S. funding of U.N. global warming programs because they were “job-destroying.”

It's an attitude shared by many of his most fervent supporters, and it has a long history.

Flanked by cabinet members and coal miners, President Trump introduced and signed an executive order on March 28, that revokes Obama-era climate regulations. (The White House)

At a 1992 conference, President George H.W. Bush and 177 other governments signed something called Agenda 21. It's a totally voluntary United Nations “action plan” that offers suggestions for way local, state and national governments can combat poverty and pollution. It's fairly innocuous and, again, nonbinding.

But antigovernment conservatives such as Phyllis Schlafly and Tom DeWeese latched onto the measure as a symbol of a much broader U.N.-backed conspiracy take control of America. DeWeese, whose think tank focuses on “the United Nations and its effect on American national sovereignty,” has described Agenda 21 as a “blueprint to turn your community into a little soviet.”

The movement that sprung up around it left no hyperbole unused. In speeches, hysterical books and DVDs and interviews, anti-Agenda 21ers call it  “the most dangerous threat to American sovereignty”; “An anti-human document, which takes aim at Western culture, and the Judeo-Christian and Islamic religions,” that will bring “new Dark Ages of pain and misery yet unknown to mankind,” and “abolish golf courses, grazing pastures and paved roads,” in the name of creating a “one-world order.”

“It's taken to extremes that turn Agenda 21 into some sort of international scheme to take down the stars and stripes,” explains Ryan Lenz, as senior investigative reporter for the Southern Poverty Law Center who studies the groups that oppose to Agenda 21. “Nationalism is about protecting one's borders. Opposing Agenda 21 is just a way of saying other countries don't have a say.”

Though most people don't know what Agenda 21 is, this argument — that fighting climate change is antithetical to American interests — has seeped into mainstream Republican thinking.

In 2012, Newt Gingrich promised to “explicitly repudiate” the plan if elected president. Former Georgia Senate Majority Leader Chip Rogers (R) “organized a four-hour, closed-door anti-Agenda briefing in October 2012" during which “attendees were told President Obama was using ‘mind control’ techniques to push land use planning, and that the U.N. planned to force Americans from suburbs into cities and also was implementing mandatory contraception to curb population growth,” according to the SPLC.

Trump's recent moves might be the movement's biggest victory yet. One article from Investment Watch Blog, which calls itself " pro-capitalism, pro-business, pro-market, truth seeker, and anti-MSM”, framed the president's proposal to shutter popular rural development agencies as “Trump Shutting Down Shadow Government Agencies That Implement Agenda 21.”

“People see Trump's actions in regards to the environment as a positive indication that he's moving forward with removing the … dictates of some international order,” Lenz said.