As the House of Representatives returns today, the Keystone XL oil pipeline is rising to the top of the GOP energy agenda -- with Republicans united in their aim to press the Obama administration for a green light on the project in any way they can.

The $7 billion Canada-to-U.S. pipeline's power to help the GOP nudge Democrats toward the defensive over jobs and fuel prices stands to color talks on extending the payroll tax cut now set to expire Feb. 29 as well as the progress of nearly every high-priority bill that moves forward during this presidential election year. Perhaps the biggest question surrounding Keystone XL, then, is how definitively the White House seals its fate within the next five weeks.

Republicans such as Sen. John Hoeven of North Dakota already are readying legislation that would empower Congress to override an administration denial of the pipeline's permit bid and allow construction to start on the 1,700-mile link between Alberta's oil sands and Gulf Coast refineries (Greenwire, Jan. 12).

Democrats are preparing in turn, looking for a White House rejection of the XL line -- which their leaders oppose as a high-emissions setback to renewable energy development -- that decouples the project as much as possible from the payroll tax cut, a still-pending tax extenders package and other dearly sought priorities.

"How the president says no is maybe the key part here in determining what avenues would be open to Republicans or TransCanada or anybody else," one Senate Democratic aide said in an interview, referring to the Alberta-based corporation behind Keystone XL.

The Democratic aide, speaking on condition of anonymity to address the situation candidly, added that the president would be best-served by running out the clock on the pipeline, waiting until the GOP-backed deadline of Feb. 21 before ruling.

"[K]nowing the Republicans are trying to attach Keystone XL legislation to any must-pass bills, including future negotiations over tax extenders," the aide said, "it may be better to use all the time available ... in order to thwart additional legislative efforts that would seek to force approval of the pipeline."

Like Rep. Lee Terry (R-Neb.), author of a lower chamber bill that would mandate a Keystone XL signoff rather than leave President Obama in charge of the project, Hoeven crafted his legislation without a time limit for environmental review of a potential new route for the pipeline through Nebraska. The Cornhusker State drove the administration's stated rationale for delaying a final decision on the pipeline on Nov. 10, citing the need for a fresh assessment of a pipeline path that would steer clear of Nebraska's sensitive Sandhills.

Hoeven used Saturday's weekly GOP radio address to amplify a new note of his party's Keystone XL messaging. In addition to more than a half-million daily barrels of Canadian oil-sands crude -- bitterly opposed by greens who lambaste it as a "carbon bomb" -- the North Dakotan noted that the XL line also would ship 100,000 barrels of domestic fuel from his state's thriving Bakken region.

"It's hard to imagine a project that is more in the national interest and the interest of the American people," Hoeven added.

Environmentalists who are charging into battle with Republicans and industry over the pipeline warn Hoeven's party that any attempt to force congressional approval of Keystone XL from the White House's purview could run into a buzzsaw.

"Congress ought to be extremely wary of turning itself into a permitting agency, and the White House, like all White Houses, will be extremely alert to anything they view as trampling on executive branch prerogatives," said Natural Resources Defense Council government affairs director David Goldston in an interview.

Payroll tax marriage?

Despite Republicans' appetite for forcing further debate over Keystone XL, which drew support from dozens of conservative House Democrats last year and counts several Senate Democratic supporters, the pipeline may not be able to return as a partner for a second payroll tax-cut bill that comes down the pike next month.

If the pipeline is divorced from the payroll tax relief, Democrats could claim a victory in the apparent backfiring of the GOP's push for the Feb. 21 deadline. As their party's Senate aide pointed out, Republicans "want the president to have to make a substantive decision on the project" rather than blaming the time crunch of their proposed 60-day window as the reason for denying the pipeline a permit.

The White House already has signaled that it would point to the Republican clock as a reason for disposing of TransCanada's application, noting that the company has yet to settle on an alternative path in Nebraska.

TransCanada spokesman Shawn Howard said the Nebraska review would not impede a potential start to pipeline construction in other states, noting that the in-state process is still awaiting the approval of a memorandum of understanding with the State Department.

A Senate GOP aide, speaking candidly on condition of anonymity, declined to rule out the next payroll tax-cut bill as a vehicle for further pipeline legislation. But, the aide added, a second linked attempt to fast-track Keystone XL "would be different and probably not so easily accepted," despite the fact that "a number of Democrats, of Senate Democrats, support the bill."

More FOIA drama

The State Department, which remains in the lead on the Keystone XL review in the run-up to Feb. 21, has so far declined to comment on the deadline other than to say it is reviewing the language passed as part of the payroll tax-cut deal on Dec. 23.

Greens continue to exert political pressure on the agency, however, over a pipeline review process they condemn as overly influenced by TransCanada. Friends of the Earth on Friday released a new batch of State Department documents obtained under the Freedom of Information Act, blasting the agency for redacting data from several meetings on the pipeline.

Coupled with other missing information in previous releases, Friends of the Earth spokesman Nick Berning wrote in a blog post, the new redactions suggest "that something went awry in State Department's review of the pipeline's likely impacts -- and that the department continues to try to hide information about what happened."

State has long defended its three-year Keystone XL review as unbiased and conducted in accordance with the law. The agency's inspector general is currently auditing that internal handling of the pipeline with Reuters reporting Friday that a final verdict on State's performance could come before Feb. 21.

Labor and business

In addition to the internal Democratic splits over the pipeline and its near-doubling of Canadian oil-sands crude import capacity, Republicans frequently point to the support of several major labor unions as proof of Keystone XL's job-creation value.

But the leaders of one top pro-pipeline workers' group, the Laborers International Union of North America, opposed the GOP bid to tie Keystone XL to the payroll tax cut and have stopped short of threatening to desert the president if he denies the project. Business Roundtable President John Engler, the former Republican governor of Michigan, acknowledged last week that labor leaders supportive of the pipeline would still be there for Obama in November.

"This is more of a rank-and-file question," Engler told reporters, mentioning a "guy in the building trades who is not working."

But with the American Petroleum Institute already airing TV spots aimed at pressuring Democrats on Keystone XL, a lack of overt bad blood with labor is unlikely to spare Obama the wrath of business groups if he nixes the pipeline.

Asked whether his group and others would turn to other pipeline alternatives if Keystone XL does not advance, Engler said: "If the president were to say 'I'm deferring a decision at this time, or not acting,' that doesn't make it go away."

Reporter Christa Marshall contributed.