WASHINGTON — Republicans will keep control of Congress, smashing predictions that Democrats might take back the Senate majority, which they gave up in 2014.

But the margin, which is currently 54 Republicans to 46 Democrats (including the two independents who tend to vote with the Democrats) will shrink in 2017. The numbers stood at 51 Republicans and 48 Democrats on Wednesday afternoon, clinching the majority. But the majority is far from filibuster proof. Republicans will still need a three-fifths majority — 60 votes of 100 senators — to shut down unlimited debate, a tactic used to kill legislation.

If Republicans keep their lead in Louisiana, they can claim 52 seats. The Louisiana runoff race between Republican John Kennedy and Democrat Foster Campbell will take place Dec. 10. Kennedy had 25 percent of the Louisiana vote on Wednesday morning, compared to Campbell’s 17 percent. Louisiana allows all candidates to appear on one ballot, with a runoff vote between the top two finishers if no one candidate receives the majority of the vote.

The Democrats flipped the Illinois seat of incumbent Sen. Mark Kirk for Rep. Tammy Duckworth, D-Ill., and the New Hampshire seat of incumbent Sen. Kelly Ayotte for New Hampshire Gov. Maggie Hassan, but the party still fell short of the five seats— or four seats and the presidency — necessary to take back control of the upper chamber.

The Democrats had 10 seats up for reelection in the Senate. The Republicans had a tougher road, with 24 spots on the line.

Retiring Minority Leader Harry Reid’s Nevada seat went to Democrat Catherine Cortez Masto. Re-elected Sen. Chuck Schumer of New York is expected to fill the leadership role vacated by Reid. Masto is making history as the first female Latina senator.

The 2014 elections marked the first time the Republicans had held the Senate majority since January of 2007.

The Republicans will also keep control of the House of Representatives as expected.

Some Democrats thought the House might be in play, though not on pace with the Senate. Democratic Leader Nancy Pelosi called FBI Director James Comey “the leading Republican operative in the country” following the FBI’s announcement — and subsequent dismissal — of further investigations into Hillary Clinton’s emails.

Senate battles also raged in North Carolina and Indiana. Both states elected Republicans,  with Todd Young winning Indiana and incumbent Sen. Richard Burr winning in North Carolina.

Looking forward, 33 seats will be contested in 2018, the next Senate election cycle. Of those seats, 23 will be Democratic. Two independents who caucus with the Democrats – Bernie Sanders of Vermont and Angus King of Maine — also face reelection. Republicans are expected to have only eight seats at stake.

With Republicans keeping control of both the House and the Senate, there is little pressure for the majority to push legislation through in the lame duck session later this month. It is also unlikely Supreme Court Justice nominee Merrick Garland will be confirmed.