Homeland Security Secretary Michael Chertoff has used authority given to him by Congress in 2005 to ignore environmental and other laws and regulations to move forward with hundreds of miles of fencing in Arizona, California, New Mexico and Texas.

The case rejected by the court involved a two-mile section of fence in the San Pedro Riparian National Conservation Area near Naco, Ariz. The section has since been built.

"I am extremely disappointed in the court's decision," Rep. Bennie Thompson, D-Miss., said. "This waiver will only prolong the department from addressing the real issue: their lack of a comprehensive border security plan."

Thompson chairs the House Homeland Security Committee. He and 13 other House democrats — including six other committee chairs — filed a brief in support of the environmentalists' appeal.

Earlier this year, Chertoff waived more than 30 laws and regulations in an effort to finish building 670 miles of fence along the southwest border. Administration officials have said that invoking the legal waivers — which Congress authorized in 1996 and 2005 laws — will cut through bureaucratic red tape and sidestep environmental laws that currently stand in the way of fence construction.