WASHINGTON — Majority Leader Mitch McConnell (R-Ky.) held onto control of the U.S. Senate Tuesday, with Republican senators winning enough seats to keep him in power despite a tough electoral map.

Republicans managed to beat back strong Democratic challenges in North Carolina, Pennsylvania, Missouri and especially Wisconsin, where Sen. Ron Johnson had widely been expected to lose to former Sen. Russ Feingold (D).

The GOP also easily held onto Ohio, where Sen. Rob Portman crushed former Democratic Gov. Ted Strickland by 21 points, and Indiana, where Rep. Todd Young surged past former Democratic Sen. Evan Bayh for a 10-point victory.

The two bright spots for Democrats were in Illinois, where Rep. Tammy Duckworth trounced GOP Sen. Mark Kirk, and Nevada, where former state Attorney General Catherine Cortez Masto edged out Rep. Joe Heck (R).

The Republicans’ unexpectedly strong showing ― and Donald Trump at the top of the ticket ― suggests voters were not nearly as turned off by Trump as Democrats had hoped. Democratic campaigns had tried aggressively to tie their opponents to the GOP standard-bearer. It also suggested Hillary Clinton was not the draw the party needed.

Still remaining to be decided were New Hampshire, where incumbent Republican Sen. Kelly Ayotte had a 1,500-vote lead over Gov. Maggie Hassan (D), and Louisiana, where there will be a run-off between the top two vote-getters on Dec. 10. (The seat is expected to remain Republican.)

As it stands, the GOP has a 51-seat majority, but that is likely to grow to up to 53.

The voters’ verdict sets up an almost immediate test for McConnell. He has to decide whether he will entertain any overtures from Democrats in hopes of showing the GOP can govern.

The decision will not be easy. Many senators will recognize the potent draw Trump had on the party’s most reliable voters, as well as many others, and be reluctant to challenge them to work with Democrats.

Republicans may prefer to look to 2018, when they have an excellent chance of adding to their majority, with just eight Republican senators up for re-election compared with 23 Democrats. And five of those Democrats are in states that typically vote Republican. That particular lineup could mean that Democrats have to wait until at least 2020 before they have another chance to win the Senate.

The success of the GOP is a particularly tough blow for Sen. Chuck Schumer (D-N.Y.), who is next in line to lead the Democratic caucus. If his party had done as most forecasts predicted, he would have been the first Jewish Senate majority leader.

Formal leadership elections for the new Senate are expected to be held next week, when Congress, which recessed in mid-September, returns to work.