A bitterly divided Congress that over the past year careened from crisis to crisis, pushed the nation to the brink of default and eventually shut down the federal government, ended 2013 on a more harmonious note, passing a defense policy bill and budget compromise with bipartisan support.

That newfound goodwill, however, won't last long in the new year.

All of the House and a third of the Senate are up for re-election in 2014, which means that lawmakers are likely to be even more partisan than they were in 2013. On top of that, House Republicans are still feeling bruised from the government shutdown in October, and Senate Republicans remain irate that the Democratic majority trimmed their power by restricting the filibuster after blaming the GOP for making this Congress one of the least productive in history.

“Congress is finishing this year less popular than a cockroach, and this kind of mindless, knee-jerk obstruction from Republicans is exactly why,” Senate Majority Leader Harry Reid, D-Nev., said as lawmakers were preparing to leave town.

Republicans, who face their own internal divisions, expect to spend much of the election-year session pounding Democrats over problems with President Obama's new health care law and for changing Senate rules to weaken the minority party.

“We're getting sick and tired of the dictatorial way the United States Senate is being run,” Sen. John McCain, R-Ariz., said.

Some of the issues left unfinished when Congress left for its holiday break include reauthorization of unemployment benefits for 1.3 million jobless Americans and a farm bill that includes food stamp benefits Republicans want to cut.

Lawmakers will also have to approve by mid-February another increase in the nation's borrowing limit to avoid a government default, a fight that already looks like it may once again paralyze Congress.

The White House insists Obama won't negotiate with congressional Republicans over another increase in the $17.2 trillion debt ceiling.

“He will not negotiate on Congress' ability to pay the bills that Congress has racked up,” White House spokesman Jay Carney said. “This is not something to be trifled with. It is not something to be horse-traded over.”

But Republicans are equally adamant that they will not support any increase — a threat that could push the nation once again to the brink of default — unless Democrats agree to unspecified concessions.

Senate Minority Leader Mitch McConnell, R-Ky., said Republicans feel they must use the negotiations to achieve something “important for the country.” But the GOP still must decide what those demands will be, said House Budget Committee Chairman Paul Ryan, R-Wis.

“We don't want nothing out of this debt limit [fight],” Ryan said. “We're going to meet in our retreats after the holidays and discuss exactly what it is we're going to try to get for this.”

Obama, who blames Congress for Washington gridlock, said the 11th-hour deals on defense and the budget left him optimistic that “2014 can be a breakthrough year for America” even though lawmakers are shifting to campaign mode.

“It’s probably too early to declare an outbreak of bipartisanship. But it’s also fair to say that we’re not condemned to endless gridlock,” Obama said. “There are areas where we can work together.”

Election-year politics will likely force lawmakers to put off the most contentious problems until 2015, though some advocacy groups are hoping that election-year pressures may also force lawmakers to act on some long-stalled issues such as immigration reform.

Immigration reform advocates say that once Republican incumbents get past the threat of facing a primary election opponent, lawmakers will be more willing to strike an immigration deal.

Republicans and Democrats also agree that action is needed on other priorities, like changes to the National Security Agency's secretive phone surveillance programs that the administration is expected to propose in January.

Congress also must decided whether to impose stricter economic sanctions on Iran despite White House protests that new restrictions would derail diplomatic negotiations over Tehran's nuclear program. A bipartisan group of lawmakers argues, however, that new restrictions would give Iran incentive to end its quest for a nuclear bomb.

"The American people rightfully distrust Iran's true intentions and they deserve an insurance policy to defend against Iranian deception during negotiations,” said Sen. Mark Kirk, R-Ill.