Senate leaders are debating a transportation bill that includes an amendment for the $7 billion Keystone XL pipeline.
Republican leaders describe Keystone XL as a "shovel-ready" project that would provide jobs and lower oil prices, while Democrats say their counterparts are too cozy with big oil companies.
Democrats failed to get the votes needed to end a floor debate over the transportation bill, however.
"Americans are screaming for more affordable oil supplies," U.S. Sen. Dick Lugar, R-Ind., said in a statement. He said his legislation on the pipeline would bring jobs "almost immediately" to U.S. taxpayers.
Lugar, ranking member of the Senate Foreign Relations Committee, had told U.S. Secretary of State Hillary Clinton he felt Keystone XL was a matter of national security.
TransCanada has said it plans build a U.S. leg of the pipeline from Cushing, Okla., to the southern Texas coast. It needs U.S. federal approval for the project, however, because Keystone XL would cross the U.S.-Canadian border.