The fate of a contentious oil pipeline remained in doubt last night after House Republicans reiterated their objection to a Senate payroll tax cut bill.

Over the weekend, it seemed that a speedy decision might be coming on TransCanada's Keystone XL, a proposed pipeline that would stretch from Canada to Texas refineries and ferry oil-sands crude. Both the House and Senate passed extensions of the soon-to-expire payroll tax cut with a Keystone XL provision attached (ClimateWire, Dec. 19).

That provision would require the president to make a decision within 60 days about the oil conduit, rather than waiting until 2013.

The timing matters, since the Obama administration has said it is likely to deny a permit for the pipeline if forced to make a decision in 60 days, before pending environmental reviews are completed about the $7 billion project's route in Nebraska. Pipeline supporters also have said delays into 2013 threaten jobs and the 1,700-mile project's viability, considering existing oil shipping agreements.

But a political fight over whether the payroll tax cut should be extended for a year, rather than two months as the Senate voted for, raises the prospect the Keystone XL uncertainty could rage on for days in Congress.

At a press conference last night, House Speaker John Boehner (R-Ohio) maintained there needed to be full-year extension of the tax cut, while Senate Majority Leader Harry Reid (D-Nev.) indicated in a statement that he would not shift his position either. House Republican leaders said they would vote today to request a conference between the two chambers to resolve the differences.

Meanwhile five moderate Senate Democrats sent a letter urging Boehner to support the Senate tax bill because of the pipeline. "The Keystone XL project is critical to the nation's energy security," wrote Sens. Max Baucus (D-Mont.), Jon Tester (D-Mont.), Mark Begich (D-Alaska), Mark Pryor (D-Ark.) and Mary Landrieu (D-La.).

Environmentalists, on the other hand, continued to slam the pipeline yesterday because of its potential to raise greenhouse gas emissions.

When asked yesterday whether the pipeline provision under consideration would lead to a rejection of it, White House Spokesman Jay Carney deferred to the State Department, which said a week ago that "an arbitrary deadline" from Congress would make it "unable to make a determination to issue a permit" for Keystone XL.