WASHINGTON - For Congress, 2015 was a year of ideological clashes, showdown votes, and harsh words. And that was just among Republicans.

It was the first year of President Obama's two terms when the GOP ran both the House and Senate. That meant a blend of compromise and confrontation. Each side won some priorities and blocked the others', a hallmark of divided government.

Republican infighting overshadowed everything for most of the year. Even interventions from on high - a first-ever papal address to Congress by Pope Francis and a Florida man's unauthorized landing of a gyrocopter near the Capitol - barely distracted from the GOP upheaval.

"There were a number of procedural snafus and dysfunctional moments that made this year much more difficult," said Rep. Charlie Dent (R., Pa.).

Congress enacted bipartisan deals recasting federal education policy, restricting government access to bulk phone records, extending highway programs, easing approval of future trade agreements and resolving a vexing problem of how Medicare reimburses doctors.

Before adjourning for the year, Congress sent Obama legislation Friday boosting defense and domestic spending in 2016, lifting a 1970s-era ban on U.S. oil exports, and extending dozens of expiring tax cuts.

"The Republican Senate majority is proving that you can still get a lot done with a president from a different party," Senate Majority Leader Mitch McConnell (R., Ky.) said Saturday.

But Republicans failed to repeal Obama's health-care law, eliminate Planned Parenthood's federal money, or block the international agreement curbing Iran's nuclear program. They fell short on closing the door to Syrian refugees; forcing the president to allow construction of the Keystone XL oil pipeline; and blocking regulations on clean water, air pollution, and greenhouse-gas emissions.

Some of the turmoil flowed from the GOP's presidential campaign, in which Donald Trump and others have profited by targeting the political establishment. Sen. Ted Cruz (R., Texas), one White House candidate, took to the Senate floor to accuse McConnell, his own party's chief, of telling him "a flat-out lie" about scheduling a controversial vote.

Plenty of GOP senators defended McConnell, but things got worse.

After years hounding by tea party conservatives, House Speaker John Boehner (R., Ohio) abruptly announced his resignation in September. It took a tumultuous month and public begging by GOP elders to persuade Rep. Paul Ryan (R., Wis.), the youthful 2012 vice presidential nominee, to take the post.