On March 22 in the Cushing, Okla., oil terminal and pipeline crossroads, Obama directed agencies “to cut through the red tape, break through the bureaucratic hurdles, and make this project a priority . . . and get it done.”

On Friday, TransCanada received the last of three permits it needed from the Army Corps of Engineers to begin construction on the 485-mile stretch of pipeline.

The permits dealt a blow to efforts by national environmental groups to slow the momentum behind the southern leg of the project — now also known as the Gulf Coast project. Those groups, including Friends of the Earth and the Sierra Club, have urged their Texas supporters to send comments to the Army Corps, which governs pipeline permits there. The groups have highlighted dangers linked to wetlands and rivers.

But the Army Corps have moved ahead. The Galveston branch on June 25 gave TransCanada the go-ahead for a stretch of the line, even though the agency said that the 36-inch pipeline would cross 654 “aquatic features."

“Please let us know when you complete your project by returning the enclosed pre-addressed postcard,” the Galveston District regulatory branch chief Fred L. Anthamatten said in his letter to TransCanada’s Houston office.