Today marks the 40th anniversary of passage of the Clean Water Act, one of the most remarkable, far-reaching and contentious laws ever enacted by Congress -- and, as we detail in "Paving Paradise," one that set a new standard for protecting wetlands.

The New York Times called it "a critical turning point in the nation’s efforts to rescue its rivers, streams, lakes and wetlands from centuries of industrial, municipal and agricultural pollution."

The bill passed at a time when the nation's waterways were clearly in big trouble and the public clamored for action from Congress.

As we note in "Paving Paradise," the bill was a bipartisan effort, with the lead sponsors Democratic Sen. Ed Muskie and Republican Sen. Howard Baker. After they got it passed, then-President Richard Nixon vetoed it.

"Nixon said he didn’t object to cleaning up pollution, but rather to the cost—an estimated $24 billion to help cities and counties across the nation stop dumping raw sewage into rivers, bays, and streams," we wrote. "That was $18 billion more than he wanted to spend.

The bill’s sponsors set out to override the veto -- something that had not yet been successfully done during Nixon's first term. In debate, they contrasted Nixon’s concern for mere dollars with the public's growing worry about the human cost of coping with a polluted world.

“Can we afford clean water?” Muskie asked his colleagues. “Can we afford rivers and lakes and streams and oceans which continue to make life possible on this planet? Can we afford life itself?”

And Baker asked, “If we cannot swim in our lakes and rivers, if we cannot breathe the air God has given us, what other comforts can life offer us?”

They succeeded in overriding the veto and the bill became law. Since then it has scored success after success at cleaning up point-source pollution -- sewer plants that once dumped their waste directly into waterways, for instance.

Yet the Clean Water Act remains controversial today, with repeated efforts by some in Congress to curtail or even kill it and a series of Supreme Court decisions that have muddied the regulatory waters.

Most of this fighting has been over Section 404 of the act, which is supposed to protect wetlands. Despite that supposed protection, the nation's wetlands have continued to decline and now are at a tipping point. To make matters worse, non-point source pollution, which is behind the rise in nutrients in the nation's waterways -- the nation's worst pollution problem -- is causing more damage to the Eastern Seaboard's salt marshes than anyone previously realized.

The decline of salt marshes means more than just the loss of the species that live there. Salt marshes turn out to play a role in slowing down climate change. In other words, saving them works to save ourselves.

If only the agency that the Clean Water Act put in charge of protecting the nation's wetlands would do its job. That's something to contemplate amid all the celebration.