Republicans have clinched Senate control in an election night that saw Democrats around the country crushed by the growing unpopularity of President Obama.

Democratic losses piled up throughout the night, with the GOP securing a Senate majority before midnight as Sen. Kay HaganKay Ruthven HaganInfighting grips Nevada Democrats ahead of midterms Democrats, GOP face crowded primaries as party leaders lose control Biden's gun control push poses danger for midterms MORE lost in North Carolina and Republican Joni Ernst won an open seat in Iowa.

Incumbent Democrats also fell in House and gubernatorial races, adding to the scale of the party's defeat. High-profile Democratic targets including Wisconsin Gov. Scott Walker (R) prevailed, and the party failed to pick up a single Senate seat. 

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The GOP needed to gain six seats to win the majority, and had already gained seven seats before polls even closed in Alaska. There, Republican Dan Sullivan has opened a lead over Sen. Mark BegichMark Peter BegichAlaska Senate race sees cash surge in final stretch Alaska group backing independent candidate appears linked to Democrats Sullivan wins Alaska Senate GOP primary MORE (D) with nearly all of the vote counted. 

Republicans won open seats held by Democrats in Montana, West Virginia, Iowa and South Dakota, and knocked off incumbents in North Carolina, Arkansas and Colorado.

Their majority could grow larger — Sen. Mary LandrieuMary Loretta LandrieuCassidy wins reelection in Louisiana Bottom line A decade of making a difference: Senate Caucus on Foster Youth MORE (D-La.) will be the underdog in a runoff election in December against Republican Rep. Bill Cassidy. Sen. Mark WarnerMark Robert WarnerOutrage grows as Justice seeks to contain subpoena fallout The Hill's Morning Report - Biden-Putin meeting to dominate the week The tale of the last bipartisan unicorns MORE (D-Va.) was also clinging to a razor-thin lead in Virginia that appeared headed for a recount.

If both Sullivan and Cassidy eventually prevail, that margin could grow to nine seats netted by the GOP by the end of the cycle. 

Sen. Mitch McConnellAddison (Mitch) Mitchell McConnellBipartisan infrastructure deal takes fire from left and right Jayapal to Dems: Ditch bipartisanship, go it alone on infrastructure The Hill's 12:30 Report: Sights and sounds from Biden's European trip MORE (R-Ky.) easily won his reelection fight, and the other wins ensure he will fulfill his long-held dream of becoming Senate majority leader.

McConnell was declared the victor in his closely watched race as soon as polls closed in the Bluegrass State, defeating Democrat Alison Lundergan Grimes to earn a sixth term. Democrats had early hopes for the Kentucky secretary of State's candidacy, but her campaign couldn't take advantage of the senator's unpopularity in the state. 

McConnell had to wait for several more hours to learn which way Senate control would fall. But the GOP leader's counterpart admitted just before midnight that Democrats had been ushered from power. 

"I'd like to congratulate Senator McConnell, who will be the new Senate Majority Leader. The message from voters is clear: they want us to work together. I look forward to working with Senator McConnell to get things done for the middle class," said now-Senate Majority Leader Harry ReidHarry Mason ReidBiden fails to break GOP 'fever' Nevada governor signs law making state first presidential primary Infighting grips Nevada Democrats ahead of midterms MORE (D-Nev.). 

The change in power means that Obama will spend the last two years of his presidency dealing with an emboldened all-Republican Congress that intends to challenge him on major legislation and, in the words of McConnell, take the country in a “new direction.”

Hagan's loss to state Speaker Thom Tillis was one of the most surprising results of the night, and her fall sealed the Democratic Party's 2014 fate.

Arkansas Sen. Mark PryorMark Lunsford PryorBottom line Everybody wants Joe Manchin Cotton glides to reelection in Arkansas MORE (D) was the first incumbent to fall on Tuesday. Freshman Rep. Tom CottonTom Bryant CottonOvernight Defense: Austin and Milley talk budget, Afghanistan, sexual assault and more at wide-ranging Senate hearing Cotton, Pentagon chief tangle over diversity training in military Media continues to lionize Anthony Fauci, despite his damning emails MORE (R) handily defeated the centrist lawmaker in a state that has slipped rapidly away from Democrats in recent years.

Colorado Rep. Cory GardnerCory GardnerBiden administration reverses Trump changes it says 'undermined' conservation program Gardner to lead new GOP super PAC ahead of midterms OVERNIGHT ENERGY: Court rules against fast-track of Trump EPA's 'secret science' rule | Bureau of Land Management exodus: Agency lost 87 percent of staff in Trump HQ relocation | GM commits to electric light duty fleet by 2035 MORE (R) knocked off Sen. Mark UdallMark Emery UdallKennedy apologizes for calling Haaland a 'whack job' OVERNIGHT ENERGY: Haaland courts moderates during tense confirmation hearing | GOP's Westerman looks to take on Democrats on climate change | White House urges passage of House public lands package Udalls: Haaland criticism motivated 'by something other than her record' MORE (D), defying Democratic cries that their vaunted ground game would save the vulnerable incumbent. 

Republicans also picked up a Democrat-held open seat in West Virginia with Rep. Shelley Moore CapitoShelley Wellons Moore CapitoGOP senator introduces constitutional amendment to ban flag burning Biden fails to break GOP 'fever' Pelosi: 'No intention' of abandoning Democrats' infrastructure goals MORE's (R) easy victory. 

South Dakota flipped to the GOP column after former Gov. Mike Rounds (R) won the open seat of retiring Democratic Sen. Tim JohnsonTimothy (Tim) Peter JohnsonCornell to launch new bipartisan publication led by former Rep. Steve Israel Trump faces tough path to Fannie Mae, Freddie Mac overhaul Several hurt when truck runs into minimum wage protesters in Michigan MORE (D). The three-way race had become a late headache for the GOP with the addition of former GOP Sen. Larry Pressler (I), but with Republican attention and help the race turned again in Republicans' favor. 

Rep. Steve Daines (R) then won the open Democratic-held seat in Montana. 

Republican leaders crowed over the victory, arguing voters had sent a strong signal about which party they want in control in Washington.

"The American people have put their trust in the Republican Party, sending a GOP majority to the U.S. Senate. I want to congratulate all our candidates tonight," Republican National Committee Chairman Reince Priebus said in a statement. "Our party's principles and message resonated with voters across the country. This was a rejection of President Obama's failed polices and Harry Reid's dysfunctional Senate."

This post was updated at 5:02 a.m. on November 5.