Cynthia Magnuson, a spokeswoman for the Justice Department, said Thursday she couldn't comment "because it's an internal e-mail."

Shown a copy of the e-mail, David Bookbinder, senior attorney for Sierra Club, remarked, "Why are they (Bush administration officials) trying to smear us like this?"

The Sierra Club and other environmental groups had nothing to do with the flooding that resulted from Hurricane Katrina that killed hundreds, he said. "It's unfortunate that the Bush administration is trying to shift the blame to environmental groups. It doesn't surprise me at all."

Federal officials say the e-mail was prompted by a congressional inquiry but wouldn't comment further.

Whoever is behind the e-mail may have spotted the Sept. 8 issue of National Review Online that chastised the Sierra Club and other environmental groups for suing to halt the corps' 1996 plan to raise and fortify 303 miles of Mississippi River levees in Louisiana, Mississippi and Arkansas.

The corps settled the litigation in 1997, agreeing to hold off on some work until an environmental impact could be completed. The National Review article concluded: "Whether this delay directly affected the levees that broke in New Orleans is difficult to ascertain."

The problem with that conclusion?

The levees that broke causing New Orleans to flood weren't Mississippi River levees. They were levees that protected the city from Lake Pontchartrain levees on the other side of the city.

When Katrina struck, the hurricane pushed tons of water from the Gulf of Mexico into Lake Pontchartrain, which borders the city to the north. Corps officials say the water from the lake cleared the levees by 3 feet. It was those floodwaters, they say, that caused the levees to degrade until they ruptured, causing 80 percent of New Orleans to flood.

Bookbinder said the purpose of the litigation by the Sierra Club and others in 1996 was where the corps got the dirt for the project. "We had no objections to levees," he said. "We said, 'Just don't dig film materials out of the wetlands. Get the dirt from somewhere else.' "

If you listen to what some conservatives say about environmentalists, he said, "We're responsible for most of the world's ills."

In 1977, the corps wanted to build a 25-mile-long barrier and gate system to protect New Orleans on the east side. Both environmental groups and fishermen opposed the project, saying it would choke off water into Lake Pontchartrain.

After litigation, corps officials abandoned the idea, deciding instead to build higher levees. "They came up with a cheaper alternative," Bookbinder said. "We didn't object to raising the levees."

John Hall, a spokesman for the corps in New Orleans, said the barrier the corps was proposing in the 1970s would only stand up to a weak Category 3 hurricane, not a Category 4 hurricane like Katrina. "How much that would have prevented anything, I'm not sure," he said.

Since 1999, corps officials have studied the concept of building huge floodgates to prevent flooding in New Orleans from a Category 4 or 5 hurricane.

Although the Federal Emergency Management Agency in 2001 listed a hurricane striking New Orleans as one of the top three catastrophic events the nation could face (the others being a terrorist attack on New York City and an earthquake in San Francisco), funding for corps projects aimed at curbing flooding in southeast Louisiana lagged.

U.S. Sen. Mary Landrieu, D-La., has said the White House cut $400 million from corps' requests for flood control money in the area.

In fiscal 2006, the corps had hoped to receive up to $10 million in funding for a six-year feasibility study on such floodgates. According to a recent estimate, the project would take 10 years to build and cost $2.5 billion.

"Our understanding is the locals would like to go to that," Hall said. "If I were local, I'd want it."