Now that we have elected a new president, environmentalists need to figure out how to survive the next four years of Trump presidency. It’s not going to be easy.

Trump has expressed outward hostility to environmental issues. He does not believe climate change is real and treats many government agencies designed to protect the environment as roadblocks to economic progress. It would not be surprising if he tries to pulls out of the 2015 Paris Agreement (he’s said he would “cancel” it, which is not something he can do) and kills the Clean Power Plan. He’ll probably approve more pipelines, relax restrictions on fracking, and allow the exploitation of resources on public lands. His support base has a strong anti-regulatory fervor, which means that chances for new environmental regulations are zero. And if current choice Myron Ebell becomes the next head of the Environmental Protection Agency, the regulations and protections we have could be cut down, or defunded to a point of irrelevance.

The 48 Democratic senators (assuming the GOP wins the Louisiana runoff) could filibuster every law that undermines environmental regulations. But Republicans could always put the environmental measures in budget reconciliation that requires just 51 votes in the Senate. (Also, who knows how the 25 Democratic senators up for re-election in 2018 will vote.)

So, what to do?

First, environmentalists should not panic. Despite saying he’d like to, the president cannot unilaterally abolish the EPA without congressional approval. Sure, Richard Nixon created the EPA in 1970 by executive order, but much water has flowed down the Potomac since then. Specifically, Congress has tasked the EPA with translating statutes that require the protection of air and water into specific rules on how we do so and then enforcing them. So, nixing the organization would violate many other laws. Trump and Ebell could probably try to defund it. This would weaken the enforcement. If this happens, it will be up to environmental groups to sue to compel the EPA to enforce the laws, an action that has vast precedent. For example, because the Endangered Species Act mandates that the government must protect species that are at a certain level of risk, environmental groups have been able to successfully sue the government to place certain species on the endangered list.

The EPA’s rules cannot be rescinded easily. By some accounts, Clinton repealed only 8 percent of the rules of his predecessor, and George W. Bush repealed only 3 percent of rules from the Clinton era. Rescinding rules requires a lengthy process including a public comment period. And new rules or the recension of old ones can be delayed by litigation, which always starts at lower courts and takes a while before it bubbles up to the Supreme Court.

Environmentalists should also remember that things looked pretty bleak for their agenda in the early 2000s, when Republicans controlled both houses and the presidency from 2003 to 2007. There was a strong anti-regulatory fervor in the White House. Dick Cheney headed the energy task force. The environmental agenda suffered setbacks—as a starter, think of the exemptions granted to fracking from several federal environmental statutes.

But the setbacks of those times were temporary and limited to the federal level. In response, much of the environmental policy innovation moved to states and cities. By some counts, cities are responsible for about 70 percent of energy-related greenhouse gas emissions. And many cities have mayors with strong environmental agendas, so progress is possible here even without federal support. Several cities already have innovative programs focused on renewable energy; mass transit; Leadership in Energy and Environmental Design, or LEED, buildings; and recycling. Taking offices in city governments should become an important political priority for environmentalists.

States, the policy laboratories of the federal system, have taken the lead on many innovative environmental programs as well. Some policies, such as renewable portfolio standards for electricity generation, have been adopted across a large number of states. In other cases, individual states have innovated in a specific area. Examples include Georgia’s brownfield redevelopment program, California’s zero-emission vehicle mandate, Florida’s urban planning mandate on land use, Maryland’s green building code, Massachusetts’ information disclosure program to reduce the use of toxic chemicals, and Ohio’s mercury elimination program. States can continue to make incremental progress.

Back at the federal level, there are also some commonalities (surprising as it may sound) environmentalists have with Trump’s outlook that may well be exploited for the benefit of the environment.

Environmentalists and Trump are both against trade, though for different reasons. Trade allows for a race to the bottom whereby the countries with the weakest environmental laws get the most business from firms who want to produce in a place without regulations on water or air pollution. Trump is against trade because he thinks America has negotiated bad trade deals and has lost in the bargain. Still, there is common ground. Trade rhetoric could provide environmentalists the necessary leverage to demand higher (and costlier) environmental standards in China, India, Mexico, and elsewhere, which would make Trump happy because it would make foreign goods more expensive. In this way, environmentalist can “export” American environmental policy abroad. Of course, trade might be a way that other countries angry with Trump’s environmental policies get even—France is already discussing a carbon tax on our goods if Trump pulls the U.S. out of the Paris Agreement.

Environmentalists could also find a way to get on board with Trump’s nativist core message to make America great again. Trump says he is committed to rebuilding infrastructure. For example, he’s lamented the state of our airports in comparison with other countries, such as Dubai and China. Well, if existing airports are replaced with LEED-certified ones (as Dubai is seeking), it will help in climate change mitigation. Or, if highways and roads are fixed so that the traffic can flow smoother, it will lower vehicular emissions. It’s possible that making America great could also make America green, if the infrastructure projects are committed to doing this in an environmentally friendly fashion. Trump may find this the right move simply because this sort of collaboration might help his re-election chances in 2020.

Finally, environmentalists must stand up against Trump when he threatens the regulations and agreements necessary to keeping our Earth inhabitable. Trump should be opposed when his policies will harm the planet, such as pulling out of the Paris Agreement, allowing drilling on federal lands, defunding the EPA, and giving permits for additional pipelines. Alongside popular mobilization against such policies, they should employ litigation; in many ways, this was a successful strategy to slow down Bush-Cheney’s attempt to undermine environmental regulations.

While vigorous opposition must continue, environmentalists should remain open to working with Trump. And they need to pay more attention to state and city level politics because this is where a lot of the real action is taking place.

Key environmental laws were enacted in the presidency of Richard Nixon. The challenge is to create an environmental Nixon out of a climate change–denying Donald Trump. We can try, and then we can fight. We have no other choice