More than 30 years ago, on December 28, 1973, U.S. President Richard Nixon signed into law the Endangered Species Act, one of the most comprehensive wildlife conservation laws in the world.

Legislators vote to enact laws that in principle, at least, affirm the will of the people. Thirty years ago, the U.S. Congress voted to protect America's natural heritage.

Driving their vote was a looming environmental crisis: extinction was threatening growing numbers of wild plant and animal species. Half of all recorded mammal extinctions had occurred in the prior 50 years. The bald eagle the nation's bird was on the brink. The American alligator was overexploited for its skin. Development sprawled into wild habitat.

The Endangered Species Act was a victory for wildlife.

"It was a time when people were concerned about the environment, protecting it and about the impact of the quality of life and waned to deal with all the values that were important in that area," said Michigan Congressman John Dingell, who co-sponsored the legislation.

In the early 1970s Congress had created the Environmental Protection Agency, the Marine Mammals Protection Act and the Clean Air and Clean Water Acts, all, says John Dingell, like the Endangered Species Act passed with wide-ranging bipartisan support.

Dingell: All of these pieces of legislation were passed by heavy bipartisan majorities, surrounded with non-controversy. And, people were happy to do them both in the Congress and outside because we knew that we were very heavily dependent for quality of life and indeed just for simple life on how we protect the world in which we live.

Skirble: What I hear you saying is that it was the right thing to do.

Dingell: It was the right thing to do and everybody knew it. And no one quarreled about it, and all this legislation passed by overwhelming majorities just in each instance just short of unanimous both in the House and in the Senate.

The law lists endangered and threatened species, designates habitats to be protected and mandates a conservation plan for recovery.

The list includes 1265 mammals, birds, reptiles, fish, insects and plants, which range from large predators like the grizzly bear and Florida panther to smaller creatures like the Carolina Northern Flying Squirrel, the Tooth Cave Spider and Lotis Blue Butterfly.

Over the years compliance has stirred controversy, especially among property owners. The Act has prompted lawsuits from across the spectrum: from citizens' groups petitioning for new listings, to those opposing its regulations. Conflicts have abounded.

A small fish called the snail darter halted dam construction in Tennessee. The timber industry was alarmed at the potential loss, when millions of hectares of Pacific Northwest forest were set aside for the Northern Spotted Owl. The Delhi Sands Loving fly delayed construction of a medical center in California, where a building had to be moved to protect habitat.

Republican Congressman Richard Pombo heads the committee in the U.S. House of Representatives charged with oversight of the Endangered Species Act. After 30 years, less than a dozen species have been de-listed, a sign, he says, that "the law is broken."

"That is a failure by anybody's measure," said Congressman Pombo.

Democratic Congressman John Dingell, who helped craft the law, disagrees.

"The Endangered Species Act has worked. It has protected the species, their environment and their habitat," he said.

The bald eagle and the peregrine falcon are success stories. The law is also credited with having restored a healthy wolf population in Yellowstone National Park, an abundance of alligators in Florida swamps, and for the protection of millions of hectares of forests, beaches and wetlands.

Richard Pombo says that has all come at too high a price. "Because of the way it is implemented, property owners and ranchers across the country are afraid that their property is going to be habitat for an endangered species," he explained. "And [that] has the opposite effect of what we had intended in the act because people begin to manage their property in such a way that it doesn't attract wildlife."

John Dingell says the law simply reflects common sense. "There are a lot of special interests that resent the fact that these species are protected, that they are not able to utilize public lands and resources and even private resources in ways that are inconsistent with a broad national policy," he said. "And, that is that we do not have the right to extinguish forms of life."

John Dingell fears attacks by the Republican-led Congress will weaken the law. But environmental activist Brock Evans, who heads a coalition to promote species survival, says most Americans don't want to weaken the law.

"Every group in American society hates the Endangered Species Act, except for one group and it's called the American people. And they love it," he said. "That can be the only reason that it has survived despite the ferocious assaults mounted in [the] House [of Representatives] and Senate and the Administration to try to repeal or weaken it in some way. Over and over again you see in every poll, everywhere you go, no one wants to see species go extinct." How effectively Americans have communicated that message to their elected representatives, and how their will is being enforced through the Endangered Species Act, are key to the survival of wildlife species facing extinction. And the fight to save them is being fought on many fronts.