In accusing the Environmental Protection Agency of trying to regulate "water itself as a pollutant," Virginia Attorney General Ken Cuccinelli is not showing an excess of exactitude. But his looseness is rhetorical and harmless. The EPA's is neither.

Last week federal judge Liam O'Grady sided with Cuccinelli when he ruled that the EPA had overstepped its bounds. As a measure of just how far the EPA had overreached, note that Cuccinelli's suit against the EPA was joined by Fairfax County, led by Board of Supervisors chairman Sharon Bulova.

Bulova, a Democrat, is nobody's idea of an environmental menace. A longtime advocate for commuter rail and mass transit, she started a Private Sector Energy Task Force to increase energy efficiency, sustainability, and "green-collar" jobs in the county. Nevertheless, she and other county leaders objected when the EPA tried to limit the amount of stormwater runoff into the 25-mile-long Accotink Creek, which empties into the Potomac. "When people talk about federal agencies running amok, this is exactly what [that] looks like," said GOP Supervisor John C. Cook in July. "The EPA's overreach is so extreme that the Democrats on the board realized that, even in an election year, they had to do this for the county."

Concerned about sediment in the Accotink, the EPA had sought to cut stormwater runoff nearly in half—a proposal that would have added perhaps $200 million to the roughly $300 million cost of addressing sediment itself.

But as O'Grady noted, while the EPA can regulate sediment, which is considered a pollutant, it has no authority to regulate stormwater—which is not.

The EPA claimed—notably, "with the support of Virginia['s Department of Environmental Quality]"—that it could regulate stormwater as a proxy for sediment itself, even though it had no legal authority to do so, because nothing explicitly forbids it to do so. As Cuccinelli said, "logic like that would lead the EPA to conclude that if Congress didn't prohibit it from invading Mexico, it had the authority to invade Mexico."

Why would the EPA insist on regulating stormwater, which it has no authority over, instead of simply regulating sediment? After all, it has written rules for sediment literally thousands of times. That insistence makes no sense. But it does look like part of a larger pattern.

Last spring, the Supreme Court ruled against the agency in the case of Mike and Chantell Sackett. The Sacketts owned a piece of land, a little larger than half an acre, in a growing lakefront development in Idaho. They were building a vacation home on the spot when the EPA declared it might be a wetland and ordered them to cease construction, and restore the land to its prior state or face fines of up to $75,000 a day. The agency decreed that the Sackettshad no right to challenge the order in court.

The Supreme Court unanimously call that bunk. It's not easy to get Justices Antonin Scalia and Ruth Bader Ginsberg on the same page, but the EPA managed to do so. The agency also drew the wrath of The Washington Post, which editorialized that "The EPA Is Earning a Reputation for Abuse." The editorial began by condemning the now-infamous remarks of now-former EPA administrator Al Armendariz, who compared his enforcement philosophy to Roman crucifixions: "They'd find the first five guys they saw and they'd crucify them. And then, you know, that town was really easy to manage for the next few years."

Troubling stories about the EPA just keep piling up. In Texas, the agency went after Range Resources Corp. for allegedly polluting two wells. The company racked up more than $4 million in fees defending itself before the EPA grudgingly admitted it had no proof Range Resources had contaminated anything.

In July, the federal district court in D.C. ruled that the EPA had overstepped its bounds regarding Appalachian coal operations. That ruling followed another concluding the EPA had no business revoking a waste-disposal permit, issued by the Bush administration, for a West Virginia mine. Judge Amy Berman Jackson—an Obama appointee—called the agency's action "a stunning power for the EPA to arrogate to itself," and accused the agency of "magical thinking."

With the possible exception of a few anarchist cells, nobody questions the need for environmental regulation—or the EPA's authority to enforce environmental laws. But those objecting to the agency's abuses—Bulova, Ginsberg, The Washington Post, Judge Jackson—are hardly anarchists. They aren't even Republicans. That ought to ring warning bells; this isn't just a partisan vendetta. The EPA's long train of abuses and usurpations suggests an institutional culture that sees the law as an impediment, rather than a guardrail. It also offers a reminder that those who wield power tend to push the boundaries of their authority. They will succeed, too—unless others push back.