As expected, the Republican Party has reclaimed control of the Senate, giving it control of both houses of the U.S. Congress for the first time in eight years. The GOP also increased its holdings in the House of Representatives; its 246 seats are its largest majority in nearly a century. Now, the GOP must decide its purpose: Will it govern in partnership with the president or will it be a conservative buzz saw, determined and unyielding, preferring defeat to legislative success if it means making a compromise?

Ominously for new Senate Majority Leader Mitch McConnell and Speaker of the House John Boehner, the choice is not clear for many members of their party. A failure to come together will focus attention on the dysfunction on the right, giving critics of Washington gridlock a clear target and boosting the case for a swing back to the Democratic Party in national elections that will be held two years from now.

A Republican victory was anticipated in this week's vote. Traditionally the party that does not control the White House makes big gains in "off year" elections, and this year GOP's prospects looked especially strong. There were more Democratic senators than Republicans up for re-election this year — beneficiaries of the Democratic tide that brought Barack Obama to power in 2008 — and most of them were in states that GOP candidate Mitt Romney had carried by double digits in his losing effort in the 2012 presidential campaign.

In other words, those states were inclined toward Republican candidates and the Democratic Party incumbents had a hard time winning again.

Republican prospects were boosted by the belief among a large majority of Americans that their country is heading in the wrong direction. In recent weeks, U.S. voters have been inundated with threats — an Ebola outbreak that has penetrated their borders, the deterioration of the situation in Iraq and Afghanistan, the rise of Islamic State, a tide of illegal immigration on the southern border that revives fears of vulnerability — and a sense that their country is no longer respected internationally. Russian President Vladimir Putin thumbs his nose at the U.S. and its partners in Europe, while China challenges U.S. pre-eminence in Asia.

This unease is anomalous, however, when voters look at their daily lives. The U.S. economy is now growing in excess of 3 percent a year, gas prices are down, the U.S. national debt is shrinking and the unemployment rate is under 6 percent.

The final factor behind the GOP victories this week was turnout. The number of voters that casts ballots in midterms is usually lower than that of presidential elections. This year, some two-thirds of voters chose not to participate, a reflection of their disgust with the political process. Those who did cast ballots were predominately older — turnout among voters age 60 and older was more than three times that of voters under 30 — and they constitute the Republican Party's base.

The question now is what the GOP will do with control of Congress. During the campaign, Republican candidates were remarkably quiet about what they stood for, apart from a repudiation of the Obama presidency. Mere opposition is the lowest common denominator among party members. While that reticence makes sense on the hustings, it does not constitute a platform to govern. The party leadership must now rally members behind an agenda that shows the GOP can do something more than obstruct the president.

In theory, progress is possible. The long-delayed Keystone pipeline could be approved and trade agreements could move forward; the fast-track authority that is the first step toward such agreements has been withheld primarily by members of the president's own party (although that is not the only source of opposition). Tax reform is also possible, and a truly forward-thinking GOP could agree on a compromise on immigration legislation.

Nothing is guaranteed, however, given the deep fissures within the GOP between "country club" Republicans who are prepared to make deals with Obama and tea party members who will not compromise their principles to pass legislation and are most interested in rolling back the Obama accomplishments of his first six years, in particular his signature health care program. If the obstructionists prevail, the next two years will be an exercise in frustration and futility.

Senate Democrats will show that they can filibuster as effectively as Republicans did during the first four years of the Obama administration. Any legislation that survives that process and does pass Congress will be sent to the White House where it will be routinely vetoed.

Regardless of which GOP emerges, two things are certain. First, much Republican congressional energy will be devoted to investigations that embarrass the Obama administration and the work of former Secretary of State Hillary Clinton in an effort to undermine her presumed candidacy for the presidency in 2016. Second, the GOP will face a similar if not greater challenge in the 2016 ballot when Republicans will be forced to defend an even larger number of seats than Democrats did in this week's election. It is very difficult to be optimistic about developments in Washington and the prospect of U.S. leadership in the world. The timing could not be worse.