The U.S. House of Representatives is pected to act on a bill is expected that links a decision on the Keystone XL oil pipeline to a measure that would extend tax cuts for U.S. workers.
U.S. President Barack Obama brushed off efforts by House Republicans to force a decision on the oil pipeline, which would carry oil from tar sands projects in Alberta, Canada, to refineries along the southern U.S. coast.
A spokesman for the State Department said Obama followed precedent by ordering a review of the pipeline proposal.
"It is the president's prerogative to lead and manage the foreign policy of the United States and in the case of the proposed Keystone XL pipeline project, our relations with Canada," the spokesman said. "This historical prerogative encompasses the president's long-established authority to supervise the permitting process for transboundary pipelines."
Backers of the project describe it as a shovel-ready project that would boost the economy and create jobs in a sluggish U.S. ecomony. Critics say Alberta crude is more toxic than conventional crude and worry about the potential long-term effects on the environment.
Concerns about the proposed crossing of Keystone XL through a Nebraska aquifer prompted a reconsideration of the route. That means the State Department has to review the alternatives and likely won't make a decision until after November 2012 presidential elections.
The House measure is expected to stall in the Democratic-controlled Senate.