Congress has legal clout on Keystone pipeline: study WASHINGTON (Reuters) - The Congress has the constitutional right to legislate permits for cross-border oil pipelines like TransCanada's Keystone XL, according to a new legal analysis released late on Friday. The study by the nonpartisan Congressional Research Service could give a boost to Republicans drafting legislation to overturn a decision this week by President Barack Obama to put the $7 billion Alberta-to-Texas project on ice. Historically, U.S. presidents have made executive decisions on pipelines that cross borders. But Congress had the power all along to weigh in on the permits, said the study, done by four legislative attorneys with the CRS. "If Congress chose to assert its authority in the area of border-crossing facilities, this would likely be considered within its Constitutionally enumerated authority to regulate foreign commerce," the study said. Republicans in Congress have elevated the Canadian pipeline and the construction jobs it would create as a top election-year issue, accusing Obama of caving to environmental groups. They pushed to include a deadline for a permit approval in a payroll tax cut bill that Obama signed into law in December. But this week, Obama and the State Department said an environmental review of a portion of the proposed pipeline could not be rushed, closing the door on a quick start to the project. The CRS report "greatly helps the conversation" among Senate and House Republicans strategizing about how to keep the project alive, said Ryan Bernstein, an energy advisor for Senator John Hoeven of North Dakota. "I think this confirms what we've been saying along - Congress has the authority to approve the Keystone pipeline," said Bernstein, who is helping Hoeven draft legislation that would see Congress green-light the project. Earlier on Friday, Republicans in the House of Representatives said they were considering using upcoming payroll tax cut or highway construction bills to force quick approval of the pipeline. Representative Lee Terry, whose home state of Nebraska would host part of the pipeline, has drafted legislation to shift the Keystone decision-making process from the Obama administration to the independent Federal Energy Regulatory Commission, which regulates pipelines in the United States.