WASHINGTON — Lame-duck lawmakers return to Washington on Monday facing a stacked agenda and not much time to get it all done before the new Congress convenes in January and a Republican takeover is complete.

Their to-do list includes keeping the government running into the new year, renewing expired tax breaks for individuals and businesses and approving a defense policy measure that has passed for more than 50 years in a row. They hope to get it all done in two weeks without stumbling into a government shutdown.

Also pending are President Barack Obama’s requests for money to combat Islamic State militants, battle Ebola and deal with an influx of unaccompanied Central American children who have crossed into the U.S.

Among the lower profile items on the agenda are renewing the government’s terrorism risk insurance program and extending the ban on state and federal taxes on access to the Internet.

Obama’s move to protect millions of immigrants from deportation proceedings and make them eligible for work permits appears to have made it more difficult to navigate the must-do items through a Capitol where cooperation already is in short supply.

The No. 1 item is preventing a government closure when a temporary funding measure expires on Dec. 11. The House and Senate Appropriations committees are negotiating a $1 trillion-plus spending bill for the budget year that began Oct. 1 and are promising to have it ready by the week of Dec. 8.

The tax-writing committees are trying to renew a bundle of expired tax breaks such as the deductions for state and local sales taxes and the research and experimentation credit. Some, like tax credits for renewable energy projects such as wind farms, are a hard sell for GOP conservatives but are eagerly sought by Midwestern Republicans such as Sen. Charles Grassley of Iowa.

The House has passed legislation that would make several of the tax breaks permanent; the Senate’s approach has been to extend them only for 2014 and 2015. Negotiators appeared close to an agreement last week only to have the White House put it on ice with a veto threat. The administration said an emerging plan by House Republicans and top Senate Democrats was tilted too far in favor of businesses.

The president’s authority to arm and train moderate Syrian rebels to fight Islamic State militants in Iraq and Syria expires Dec. 11. Lawmakers probably will renew it while postponing action until 2015 on a broader, new authorization to use military force.

Obama also is requesting more than $5 billion to pay for sending additional noncombat troops and munitions to Iraq and cover other military and intelligence costs associated with fighting the militants. He wants $6.2 billion to tackle Ebola at its source in West Africa and to secure the U.S. against any possible outbreak. Also pending is a $3.7 billion request to address the immigrant children.

Legislation to renew the government’s terrorism risk insurance program, which expires at year’s end, is eagerly sought by the construction, real estate and hospitality businesses. But negotiations between the chairman of the House Financial Services Committee, GOP Rep. Jeb Hensarling of Texas, and Senate Democrats, including Charles Schumer of New York, appear to have stalled. The program serves as a backstop in the event of a terrorist act that causes more than $100 million in losses.

The annual defense authorization bill has passed every year for more than five decades, and the chairmen of the House and Senate Armed Services committees are eager to avoid breaking the streak. Rep. Howard “Buck” McKeon, R-Calif., and Sen. Carl Levin, D-Mich., are both retiring after long tenures in Congress. Negotiators remain at odds over the Pentagon’s cost-saving proposals to trim military benefits.

Facing diminished budgets, three defense secretaries — Robert Gates, Leon Panetta and Chuck Hagel — have said the cost of personnel benefits have become unsustainable and threaten the Pentagon’s ability to prepare the military for fighting a war. Military pay and benefits account for the largest share of the budget, $167.2 billion out of $495.6 billion.

The Defense Department has proposed a slight increase in pharmacy copayments and a gradual reduction in the basic allowance for housing, from 100 percent for off-base housing costs to 94 percent.

The Senate Armed Services Committee endorsed the cuts, but the House committee rejected them.