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Another all-but-certain battle over the fate of the Keystone XL pipeline is fast approaching as the White House signals resistance to a new Feb. 21 deadline for approval of the project and interest groups step up their campaigns.

The White House agreed to the new deadline as a part of Republican language inserted in the recently passed payroll tax cut extension, but with that deadline now looming, the White House appears hesitant to meet it.

"The State Department has been very clear that that does not allow for the kinds of reviews that are necessary," White House spokesman Jay Carney said last week of the fast approaching deadline.

The State Department has the final say in approval of the pipeline because it crosses international borders. It has been reviewing the proposal for three years.

Pipeline supporters say that several environmental reviews of the proposed pipeline have already been conducted and that the White House is stonewalling under competing pressures from two of its core constituencies -- on one hand big labor, which wants a piece of the thousands of jobs the pipeline would bring, and environmentalists on the other hand, who abhor the further reliance on fossil fuels that the pipeline would bring.

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To pressure the White House, congressional Republicans and their allies in the oil industry -- headed by the American Petroleum Institute -- have begun a media campaign in support of the pipeline.

An ad run by API begins with the voice of a narrator saying Obama "promised," followed by a statement from the president that he "will do whatever it takes to put this economy back on track."

The narration continues: "Now is his chance. The Keystone XL pipeline is ready to be built bringing energy from Canada to power our country safely and responsibly and employing thousands immediately."

A similar video is now running on the website of House Speaker John Boehner. It features a music soundtrack and written text which reads, "If you were president in a struggling economy, burdened with excessive regulation and debt, and you had the chance to help create thousands of new jobs, all you had to do was approve a jobs project funded entirely with private investment, proposed more than three years ago, passed environmental reviews, preferred by your own State Department, strong bipartisan support in Congress, what would you do?"

Environmentalists have accused Boehner of investing $10,000 to $50,000 each in several different firms that have a stake in Canadian oil sands. Boehner's spokesman Michael Steel said in a recent interview that Boehner's financial adviser chooses his investments so "there's no conflict of interest on this or any other investment."

At the same time, North Dakota Republican Sen. John Hoeven, a pipeline supporter who delivered the party's weekly address on Saturday, has written legislation that would allow Congress to approve the pipeline, even if the Obama administration rejects it.

He dismissed the White House contention that the deadline next month does not permit enough time for environmental review.

"Nothing could be further from the truth," Hoeven said. "Our bill puts no time limit whatsoever on the administration's ability to review and set the pipeline's route through Nebraska, which was the only area of contention left."

Environmentalists are confident that the State Department will reject the pipeline given what they believe is the narrow timeframe for review. They plan a Capitol Hill rally later this month targeting congressional supporters of the pipeline.

Canadian Prime Minister Stephen Harper has promised that he would consider selling oil from Canadian tar sands to Asian customers if the U.S. rejects the North American route.