A GOP bill to renew a payroll tax cut will also fully replenish the U.S. Social Security Trust Fund payroll taxes support, House Speaker John Boehner said."We're continuing to talk to our members," said Boehner, R-Ohio, ahead of a closed-door House Republican conference meeting Thursday morning, scheduled to coincide with a private meeting of House Democratic leaders at the White House.The Oval Office meeting is set to begin at 10:15 a.m. EST, the White House said.Besides a one-year extension of the Social Security payroll-tax holiday, lawmakers were expected to grapple with a measure to keep the federal government funded past Dec. 16.House Republican leaders have indicated they would announce in the coming days a bill that includes the payroll-tax holiday extension. Boehner did not say Wednesday when GOP lawmakers planned to advance the measure, or how the bill would replenish the trust fund.Payroll-tax contributions from workers and employers go into the fund. Benefit payments to retirees, their survivors and people with disabilities, as well as general administrative expenses, are paid by the fund.Boehner said GOP lawmakers were considering attaching to the tax-cut bill a provision to expedite construction of a pipeline system to transport synthetic crude oil and diluted asphalt, tar and other road- and roof-surfacing materials to several U.S. destinations from Alberta, Canada.The Keystone XL faces lawsuits from oil refineries and criticism from environmentalists and some lawmakers. The State Department has asked federal agencies to decide if the pipeline is in the national interest.President Barack Obama last month postponed the decision until 2013. Senate Republicans introduced legislation Nov. 30 seeking to force Obama to approve the pipeline within 60 days unless Obama declares the project is not in the national interest.The president said Wednesday he would reject any GOP attempt to force his hand by tying Keystone to extending the payroll tax cut.A Boehner spokesman responded: "We are working on a bill to stop a tax hike, protect Social Security, reform unemployment insurance and create jobs. If President Obama threatens to veto it over a provision that creates American jobs, that's a fight we're ready to have."Obama has been prodding Congress to approve an extension and expansion of the payroll tax cut, which expires Dec. 31 and has saved an average family $1,000 this year.Republican leaders, while largely supporting the tax cut, have balked at a proposal from Obama and Senate Democrats to raise taxes on people earning more than $1 million a year to pay for it.If an agreement is not reached, virtually all wage earners would be hit with a tax increase Jan. 1.