Congress returned Tuesday to deal with unfinished business from 2015 and to forge a legislative agenda that could shape the 2016 presidential and congressional elections. A look ahead:

HEALTH CARE

The House will vote on a measure this week to repeal the Affordable Care Act, President Obama's legacy accomplishment. The bill would strip key elements from the ACA, including the individual mandate to have insurance or pay a fine and the employer mandate to offer insurance. The measure also contains a provision to eliminate federal funding for Planned Parenthood, a goal of conservative Republicans.

This is the health care repeal bill that the Senate passed before adjourning for the holidays. If the bill clears the Republican-controlled House, it would be the first ACA repeal measure to reach Obama's desk. Obama would certainly veto it. Still, Republicans view getting it through both chambers of Congress as a symbolic victory they can take on the 2016 campaign trail.

SYRIAN REFUGEES

Republicans intend to battle Obama's plan to bring 10,000 Syrian refugees to the United States, fearing that the Islamic State in Iraq and the Levant and other terrorists could enter the country through the resettlement program.

Senate Majority Leader Mitch McConnell, R-Ky., placed a House-passed bill on the Senate calendar that would restrict the flow of Syrian and Iraqi migrants. Senate Minority Leader Harry Reid, D-Nev., has signaled that the bill will go nowhere.

This could present problems for House Speaker Paul Ryan, R-Wis. Several conservative Republicans expressed displeasure that the omnibus spending bill didn't include measures to stall or prevent Obama's resettlement plan.

Last month, 95 of 246 House Republicans voted against an omnibus government spending bill Congress passed, in part because it didn't address the Syrian refugee issue.

THE ISLAMIC STATE in Iraq and the Levant

While the debate over Syrian and Iraqi migrants rages, Ryan said he'd like Congress to pass a war powers resolution against ISIL. "It would be a good symbol of American resolve to … thoroughly defeat and destroy [ISIL]," he said last month.

Depending on how such a resolution is crafted, lawmakers could find a receptive White House. Obama, in a televised speech last month, said, "If Congress believes as I do, that we are at war with ISIL, it should go ahead and vote to authorize the continued use of military force against these terrorists."

Criminal justice overhaul

Obama wants it, most of the 2016 presidential contenders want it, and the House and Senate have proposals to do it.

Revamping the nation's criminal justice system may be one of the few areas where the political parties and differing ideologies find common ground. And it will be difficult.

Senate Democrats have concerns about a House bill that they say would make it more difficult to sue corporations. The Senate bill made it through a committee in October with provisions that limit mandatory minimum sentences for nonviolent offenders and give judges more leeway in some sentences.