Republicans weighing which must-pass legislation they should use to attempt a fast-tracking of the Keystone XL oil pipeline -- a transportation bill or a payroll tax cut package -- may have a compelling third option: wait.

No one in the GOP or Washington business circles questions the political wisdom of working to make President Obama and his party answer to voters for his denial of a $7 billion project that stands to create jobs and diminish Middle Eastern oil imports. But multiple signs from Capitol Hill this week suggest that attaching the pipeline push to either the transportation or the payroll tax cut bills would end in little but a Senate stalemate.

The payroll tax cut option seemed to get a boost when Senate Finance Chairman Max Baucus (D-Mont.) told E&E Daily on Tuesday that he had "not taken [Keystone XL] off" the table for inclusion in a deal extending White House-backed Social Security tax relief until 2013. However, House Ways and Means Chairman Dave Camp (R-Mich.) said the next day that his Democratic counterpart's support for the XL line did "not necessarily" make it more likely to hitch a ride on the bill.

The transportation option also offers upsides of its own for Republicans who hail the pipeline's promised 700,000-plus daily barrels of Canadian oil sands crude. Both parties' leaders are so eager to approve a long-term infrastructure bill, which stands to create tens of thousands of jobs, that attaching a Keystone XL provision could face far less resistance than a stand-alone measure.

Yet Senate Environment and Public Works Chairwoman Barbara Boxer (D-Calif.) put the House GOP on notice yesterday that she does not intend to let "controversial items" weigh down a transportation package she worked to craft alongside the ranking committee Republican, Sen. James Inhofe of Oklahoma (see related story).

"Senator Inhofe, he'd love to see more offshore drilling and the Keystone pipeline" in the infrastructure bill, Boxer said yesterday. "I'd love to have seen more efforts to decrease carbon emissions. We stayed away from these controversies. Why? because [millions of] jobs are at stake."

Republicans on both sides of the Capitol remain in discussions about how to proceed. But several of the party's senators suggested that they had not yet coalesced behind a strategy to advance Keystone XL, which is among the oil industry's highest priorities for the year.

Even as he predicted that "there is a role Congress can play in this," Sen. John Thune of South Dakota, the third-ranked GOP leader, acknowledged that "it's difficult in Congress simply because the president is so dug in on this that Democrats who might otherwise be for it" would prove a hard sell on the project.

"Whether it moves or not remains to be seen," Thune added.

Sen. Lindsey Graham (R-S.C.) urged his side of the aisle to "pick a vehicle that makes sense" and "try in a smart way" to push the pipeline past the veto Obama issued last week. "To solve one problem, you don't want to create new ones."

House Majority Leader Eric Cantor's (R-Va.) office referred questions on the GOP's strategy for taking up Keystone XL to Speaker John Boehner's (R-Ohio) office, which did not return a request for comment in time for publication.

What is Plan C?

The payroll tax cut and transportation bills are likely the only legislative stages for a new Keystone XL bill during the first quarter of the year, but the chief sponsor of the House GOP's favored pipeline legislation stopped short of ruling out a bid to push the project through in the spring.

"If the timing and the vehicles aren't right, we need some degree of patience," Rep. Lee Terry (R-Neb.) said in an interview.

"But there is a method to the timing madness," Terry added. "Refinery companies have contracts for delivery of that oil in 2014 ... the later we wait, the more likely there are to be breaches of those contracts."

A "worst-case scenario," as Terry put it, would see the second quarter of 2012 pass with Congress failing to achieve an end run around Obama's denial of a permit to Alberta-based TransCanada Corp.

Yet even if Republicans pass up potential opportunities to vote on unraveling the president's Keystone XL veto, his rejection remains a potential campaign-trail wedge issue -- particularly in swing states such as Indiana and Pennsylvania that would have seen an economic boost in supplying equipment for the project.

"Several folks in the industry are no longer convinced that it is in the best interest of the project ultimately getting to 'yes' to keep forcing the issue legislatively," one refinery lobbyist said, speaking candidly on condition of anonymity. "A series of 'no's makes it harder to shift to 'yes' in 2013."

Adding the pipeline to the payroll tax bill is "not a real option," the lobbyist asserted. "The only avenues are stand-alone or the highway bill. The latter will still be subject to conference, where Keystone XL [likely] becomes an item that gets traded away at the table."

Enviros bite back

No matter what approach Republicans choose to push for Keystone XL, the same green and liberal groups that loudly cheered Obama's denial are guaranteed to return with grass-roots lobbying campaigns against the pipeline.

TransCanada got a taste of the environmentalist resistance yesterday when Greenpeace filed a complaint with the Securities and Exchange Commission that accused the pipeline operator of making false statements about the number of jobs the XL line would create in order to win approval of the project.

"Specifically, [TransCanada] has asserted that each mile of ... pipeline constructed in the U.S. would create American jobs at a rate that is 67 times higher than job creation totals given by the company to Canadian officials for the Canadian portion of the pipeline," the conservation group wrote to SEC Chairman Mary Schapiro.

TransCanada, the oil industry, and Republicans estimate that Keystone XL would generate 20,000 jobs in construction and manufacturing as well as more than 100,000 spinoff jobs. Environmentalists point instead to the job-creation data the company submitted to the State Department during its review of the project, which cited up to 6,500 largely short-term jobs created annually over the project's two-year construction horizon (E&E Daily, Oct. 24, 2011).

Keystone XL's sponsor fired back at conservationists' job-creation charges, which have given Democrats an opening to vocally push back at GOP advocacy for the project.

Greenpeace's complaint is "false and without merit," a TransCanada spokesman said in a statement, adding that it and other green "groups have never built or operated a pipeline. They do not understand the requirements that a company like ours has to follow -- every day. We have been operating for more than 60 years -- we know exactly what it takes to build a project like Keystone XL, which is the largest infrastructure project on the books in the U.S. right now."

Click here to read Greenpeace's letter to the SEC on TransCanada.

Reporter Emily Yehle contributed.