In national politics, California may be seen as Exhibit A for over-regulating the environment. But anyone making that argument must ignore what the state was like before the Environmental Protection Agency — smog-encrusted, water-polluted and barely able to retain its ecological luster against crushing population gains. Since the agency’s creation, its rules and enforcement have made California a livable, thriving, if oft-head-scratching place still hospitable toward business.

Now, if you’re a Republican presidential candidate irate about America’s wheezy economy, it’s easy to go Queen of Hearts and call for guillotining the E.P.A. Scapegoating regulators as job-killing obstructionists has long been used to pump up the faithful, but it doesn’t reflect well on America’s environmental maturity. None of the White House hopefuls mention the expected $2 trillion in health and environmental benefits from the Clean Air Act by 2020. Few of the greenhouse skeptics, in fact, even broach fresh air at all, perhaps because they hail from states where it was never toxic.

So the next time Michele Bachmann promises to dissolve the Nixon-created E.P.A., perhaps she should do it in Burbank, northwest of downtown Los Angeles. Decades earlier, Bachmann might have had trouble even finding the town through the eye-stinging, russet-brown air pollution filled with ozone, heavy metals, lead and other nasty byproducts of the California car culture. After a quarter century battlng the-then Big Three Automakers to produce cleaner cars, California lobbied the federal government for the right to set stricter tailpipe-exhaust standards than the rest of the country, and that campaign later helped inspire formation of the EPA itself.

Today, the teeming suburb once home to the defense contractor Lockheed Corp. and other industrial behemoths is on the mend. When the defense contractor and others like it packed up, they left dangerous contaminants behind in the soil. Thankfully, the E.P.A. endured years of legal finger-pointing and declared it a Superfund site that led to construction of grounwater filtration systems. Because Burbank and adjoining Los Angeles and Glendale partly depend on local aquifers, hundreds of thousands of people were protected from carcinogenic water that might’ve otherwise wrecked their lives.

Manufacturers once polluted willy-nilly in California, until it was chastened by the big gun known as the E.P.A. For the last thirty years, the agency has hastened dozens of other cleanups in California, from leaching chemicals at Bay Area military sites to polluted groundwater in the San Gabriel Valley. It’s cleaned up rivers, scolded regional agencies when needed, gone after rogue polluters and even helped Southern California establish the planet’s first smog cap-and-trade. While anti-regulatory politicians like to mock California for its environmental whackiness, it still boasts the world’s eighth-largest economy.

It’s actually the agency’s  cautiousness, and not over-zealotry, where it has taken its lumps here in California. There’s still, for instance, no national water health standard for chromium-six, the solvent that Erin Brockovich crusaded against in remote Hinkley, Calif. The upshot? Susceptible people lack a guardian with regulatory brawn, and state officials are no match for corporate lobbyists.

Imagining a California without an E.P.A. is visualizing a landscape where dangerous smog returns, compromised aquifers are unusable and only the suicidal would live near a factory. Better to have an inconsistent watchdog than none at all, no matter the campaign bluster from politicians with surface understandings of our ecological behavior.