In particular, the Trump administration has assailed the ESA since January. President Donald Trump’s own state of North Dakota is led by a governor, Doug Burgum, who last year signed the bill weakening the ESA and this year compared the law to the fictional “Hotel California.”

Agencies have been ordered to revise ESA rules this year in ways that would speed up fossil fuel projects by sidestepping environmental reviews.

In this context, Burgum and others paint the law as ineffective, a rigid process that does little to actually facilitate recovery. Scientists and environmental lawyers point out, however, that the ESA’s flaws are less inherent than artificial, resulting from underfunding and the stop-and-go nature of its enforcement over the years.

“We continue to wait until species are in dire straits before we protect them,” said David Wilcove, a professor of ecology and evolutionary biology at Princeton University. “That makes recovery far more difficult and expensive.”

Conservation Experts Dispute the Critiques

In fact, Wilcove and other scientists point out, the ESA has also been a successful story of prevention, not just recovery. Since 1973, only 26 listed species have been lost while under federal protection. At least 47 species are believed to have gone extinct after having been identified but not yet listed.

“The ESA works more like a critical care unit than a hotel,” Wilcove said. “It’s as though we built a great hospital but never funded enough doctors or equipment.”

The most famous example is the bald eagle, a protected species since 1967. But when the pesticide DDT and habitat loss had left only a few hundred nesting pairs in the lower 48 states by the mid-1970s, federal protections alone were not enough to make a difference. Numbers began climbing after DDT was banned in the late 1970s and a recovery plan put in place when the eagle received ESA protections in 1978. By 2007, the bald eagle was removed from the endangered list, with nearly 10,000 pairs across the country.

Other species, from American alligators and Steller sea lions to Indiana bats, have also thrived in recent decades with specific habitat protections under the ESA.

Conservationists point out the act’s protections cover public and private property, which is a major source of conflict over the ESA’s implementation. More than two-thirds of listed species rely on private land for survival, and about 10 percent exist only on such property.

“The use of your land is going to be limited and you can be prosecuted,” Jonathan Adler, a law professor at William & Mary who specializes in environmental law, told Inside Climate News. “That discourages landowners from cooperating.”

A 2017 study published in the Proceedings of the National Academy of Sciences suggested these rules have created “perverse incentives” where “landowners manage private land with an eye to the restrictions” they might face if an ESA listing is triggered. A study on red-cockaded woodpeckers found timber was harvested earlier in areas where the species was known to live, presumably to pre-empt federal habitat restrictions.

Congress has long tried to incentivize cooperation with the ESA via tax breaks and easements that limit development and offset land values in exchange for conservation efforts, but their numbers have dwindled in recent years.

Is the Endangered Species Act on the Verge of Unraveling?

A lot rides on how that case is decided and interpreted by the court, which is now more conservative-leaning. Wilcove and other experts believe that combined with Trump’s aggressive rollback of environmental protections in recent years, the ruling could curb the reach of the ESA for decades to come, if not permanently.

Compounding the ESA’s ongoing struggles is a host of other threats, many of which have become more acute in recent years. Habitat loss is ongoing, particularly as energy and infrastructure development ramps up. Climate change is thought to imperil thousands of species, though legal experts say the law could be applied more robustly to address climate change impacts.

Andrew Mergen, a former Wildlife and Parks Service lawyer who spent more than two decades litigating ESA cases for the National Wildlife Federation and now teaches at Harvard Law School, believes the answer is not further deregulation, but to “turn the law’s volume way up” in terms of resources and recovery support.

“The law has proven itself time and time again to keep species off the endangered list,” he said. “The ESA has prevented extinctions. The real challenge going forward is can we put the political and financial resources behind it to help those species recover, rather than trying to dismantle the safety net that keeps them from going extinct.”