The House has rejected a Senate-passed bill that would extend the about-to-expire payroll tax cut for individuals, setting the stage for a end-of-year showdown between the two chambers.

The Senate on Sept. 17 had approved a $33-billion package, which the Obama administration supported, to continue the tax reduction for two months past its current Dec. 31 expiration date.

But House Republican leaders, who say they want a year-long extension for the tax break, pushed through a bill on Dec. 20 that in effect rejected the Senate measure by calling for a conference to reconcile the House- and Senate-passed bills.

After the vote, House Speaker John Boehner (R-Ohio) called on President Obama to “show real leadership” and urge top Senate Democrats to agree to come back from their just-started recess and iron out differences between the two bills.

Meanwhile, Senate leaders and the president say is up House GOP leaders to approve the two-month tax-cut extension that the Senate had cleared. Obama said the  “bipartisan compromise that was reached by the Senate…is the only viable way to prevent a tax hike on Jan. 1."

Both bills also contain a controversial provision to speed approval of the proposed Keystone XL pipeline, which would carry crude oil 1,661 miles, from Alberta through the U.S. Midwest to the Gulf of Mexico. The project’s supporters, which include Republican leaders and the international pipefitters' union, say the pipeline would create thousands of construction jobs.

But some Democrats and environmental groups say the Keystone XL provision, which would eliminate the need for a full analysis of the pipeline’s potential environmental impact, essentially would kill the project.

Susan Casey-Lefkowitz, director of the Natural Resources Defense Council international program, says, "The Republican stampede to build the Keystone XL tar sands pipeline is going to backfire. In forcing President Obama to reach a hasty decision—which he has said he would not do—the president will have no choice but to reject the pipeline as not in the national interest.”