Environmental law in the United States can be a double-edged sword.

"I think that when people think about environmental law, very frequently what they mean is environmental protection, and what that misses is the other side of the coin, that there is a whole lot of law that is meant to exploit the environment," says law professor Brig Daniels.

When Daniels and his writing partner Alejandro Camacho looked at the literature available on the development of environmental law in the United States, they found it lacking.

"Most sort of focus only on environmental protection laws emerging from the 1970s or possibly the progressive era, missing frankly centuries of legal history that drove exploitation," says Camacho.

They hope to remedy this with their new book, Lessons for a Warming Planet: A Vital History of US Environmental Law.

From colonial expansion that deprived Native Americans of their ancestral lands to modern day battles over the Clean Air Act, Lessons for a Warming Planet offers a broad history of how environmental law has been developed. Change can happen gradually, or all at once. Camacho and Daniels have identified five different eras with dominant ideologies, some pushing towards protection and others towards exploitation. But in all eras, there were elements of both, the authors say.

"It isn't just a black and white sort of binary of any of these eras," Camacho tells host Lee Rawles in this episode of the Modern Law Library. "And of course, what often happened is that an undercurrent in any given era becomes the dominant era in a subsequent era."

The latest era of environmental law is one of contention, without a dominant force yet emerging. Lessons for a Warming Planet warns that either exploitation or protection could hold sway in the next era.

"The thing that I hope that people understand is that looking back, one of the things that is so prevalent is that we didn't get the history that we had due to luck," says Daniels. "A big chunk of way we got our history was due to effort."

In this episode of the Modern Law Library, Camacho, Daniels and Rawles discuss the Homestead Act, Cuyahoga River fires, and what Nixon really thought of pesky environmentalists.