House Democrats didn't see 'blue wave' to expand majority. Here's what we know.

WASHINGTON – While Democrats will likely hold their control of the House of Representatives, Republicans had big wins for Tuesday's election that could narrow Democrats majority.

Republicans flipped back several key seats that Democrats won in the 2018 midterms, unseating freshmen incumbents in South Florida, New Mexico, Oklahoma, South Carolina and Iowa, as well as a Minnesota lawmaker who was one of the chamber's longest-serving members.

“We thought we were seeing something like a blue wave across the country that would push several of these seats in the Democratic direction. And obviously, that didn't happen,” said Steven S. Smith, an expert on congressional politics at Washington University in St. Louis.

GOP candidates also defended key seats in Texas, many that were thought to be vulnerable in suburban areas, while Democrats captured two previously Republican seats that were redistricted under court order and a third seat in the Atlanta suburbs.

"Republicans defied the odds and grew our party last night. In districts all across the country, Americans rejected socialism and voted for freedom," House Minority Leader Kevin McCarthy wrote in a tweet Wednesday. "Nancy Pelosi: you've been put on notice."

Prep for the polls: See who is running for president and compare where they stand on key issues in our Voter Guide

CHECK THE MAP: Live election results from House races

Democrats had hoped to build on the majority they established during the mid-terms two years. Prior to polls closing Tuesday, Rep. Cheri Bustos, D-Ill., the chairwoman of House Democrats' campaign arm, and House Speaker Nancy Pelosi said Democrats would not only defend the gains Democrats made in 2018, but predicted the party could flip districts previously thought to be in safe Republican territory.

'Everybody in Washington is pretty shocked':Democrats, GOP grapple with mixed emotions over election

But the continuation of the 2018 "blue wave" fell short this year. On the Senate side, the battle for control got even tighter overnight.

As of Wednesday afternoon, Democrats have 194 to Republicans' 185 seats, with 56 races yet to be called, including several key races in Iowa, New York and California. To control the House, 218 seats are needed.

Here are some key takeaways from Tuesday.

GOP on the offense

Republicans flipped back several key races that Democrats had won in 2018 that helped them win the majority in the House.

Democrats saw losses by two freshman congresswomen in districts that represent Miami-Dade County, Florida's most populous county.

Democratic Rep. Debbie Mucarsel-Powell, who ousted a GOP incumbent two years ago, lost her race against Miami-Dade Mayor Carlos Gimenez in Florida's 26th Congressional District.

Democratic Rep. Donna Shalala, who won an open seat in 2018 that had been held by a Republican, lost in a rematch in Florida's 27th Congressional District to the Republican she beat two years ago.

Broadcast journalist María Elvira Salazar unseated Shalala.

President Donald Trump’s message that electing Democrats would lead to socialism seemed to resonate in this South Florida district where Cuban Americans, many who fled Fidel Castro’s authoritarian regime, flocked to Trump. Both Salazar and Gimenez are Cuban American.

“Today was a rejection of extremism. Today was a rejection of partisanship. Today was a rejection of socialism and the evils of socialism and communism,” Gimenez said at a victory party Tuesday night. “This country needs to start to work together because we have threats from outside and inside and for us to keep fighting, it makes no sense whatsoever.”

South Carolina’s 1st Congressional District: Freshman Rep. Joe Cunningham was defeated by Republican challenger Nancy Mace in South Carolina’s 1st Congressional District.

Cunningham was one of the dozens of Democrats in 2018 who flipped Republican-held districts. His seat wasn’t expected to flip to Republican control and was rated as leaning Democratic by the Cook Political Report.

Before Cunningham, the district was a Republican stronghold that the party held for every election since 1981. Trump also won the district in 2016 by about 13 points.

New Mexico's 2nd Congressional District: Democratic Incumbent Xochitl Torres Small lost her rematch to Republican Yvette Herrell.

Two years ago, the Democrat won the seat vacated by incumbent Republican Steve Pearce by beating Herrell in one of the nation’s closest congressional races. This time, Herrell won the sprawling district that borders Mexico, and by a convincing margin.

Election updates:Biden campaign officials contend he's on track to take Electoral College, but battleground states still up for grabs

Minnesota's 7th Congressional District: Rep. Collin Peterson, who represented his rural Minnesota district for three decades, lost a tough bid for reelection Tuesday against former Lt. Gov. Michelle Fischbach, even as Joe Biden won the state against Trump.

With nearly 92% of the vote counted, Fischbach was leading comfortably with 54% to 40% for Peterson.

Peterson had touted his work on the farm bill and trade deals that helped his agrarian district. But he was also fighting to keep a district that Trump won by more than 30 percentage points over Hillary Clinton in 2016.

Peterson chairs the House Agriculture Committee, an important panel for his agriculturally rich district, but it's unclear whether he will be able to fend off Fischbach, the state's former lieutenant governor.

Oklahoma's 5th Congressional District: Freshman Rep. Kendra Horn has conceded Oklahoma's 5th Congressional District race to Republican challenger Stephanie Bice.

Horn, a prominent moderate, helped Democrats take control of the district for the first time in nearly 50 years in an area that Trump won by about 13 points. She is the latest of a group of freshman Democrats to lose reelection for a second term.

Democrats fend off tough challenges

While several Democratic freshmen were defeated, a number of others managed to survive close calls.

Cindy Axne in Iowa's 3rd District, Elissa Slotkin in Michigan's 8th District and Elaine Luria in Virginia's 2nd District all won re-election.

Luria was able to beat back a challenge from former Rep. Scott Taylor, whom she had beaten two years ago. Taylor's campaign was dogged by charges of election fraud stemming from his race against Luria two years ago.

Slotkin bested GOP challenger Paul Junge, a former television anchor who tried to paint her as a partisan lawmaker who didn't adequately represent her suburban Detroit district in part by by voting to impeach Trump last year.

Axne narrowly beat former GOP Congressman David Young in a rematch of the contest the Democrat win in 2018.

Still haven't been called

Iowa's 2nd Congressional District: Republican Mariannette Miller-Meeks is holding a 282 vote lead over Democrat Rita Hart, as they compete to fill the seat left open by Democratic incumbent Rep. Dave Loebsack, who announced he was retiring last year.

Miller-Meeks has previously run for the 2nd District seat in 2008, 2010 and 2014, where she lost to Loebsack. Prior to Loebsack being elected in 2008, Republican Jim Leach represented the district for decades.

The vote counts available Tuesday night are unofficial until officials canvass the district's returns. Absentee ballots can still be counted if they're delivered to county auditors' offices by Monday, Nov. 9, at noon. Provisional ballots must also be counted before the results are certified.

New Jersey's 2nd Congressional District: Rep. Jeff Van Drew, an incumbent freshman that switched from Democrat to Republican last year, holds a slight lead against Democrat Amy Kennedy, whose family is a political dynasty.

The race has yet to be called, with roughly 75% of the votes in.

Van Drew gained widespread notoriety after switching from the Democratic Party to join Republicans during Trump's impeachment trial. The move was jarring given Van Drew helped flip the district, which Trump won by nearly 5 points, over to Democrats.

His switch garnered praise from Trump, who invited him to the White House where Van Drew promised Trump his "undying support."

California's 21st Congressional District: Rep. TJ Cox, the freshman Democrat elected to California's 21st Congressional District, is currently trailing Republican David Valadao.

Results for the race are still coming in, and it has not been called by AP.

The pair went head-to-head in 2018 and Cox came out on top, defeating Valadao by 862 votes. Cox will be facing Valadao in the aftermath of multiple scandals over business dealings and unpaid federal taxes.

The district was won by Barack Obama and Hillary Clinton by double-digit margins.

More:Polls showed Biden had a lead. Why didn't Americans wake up to a winner?

New York's 11th Congressional District: Rep. Max Rose is facing a bitter race against Republican Nicole Malliotakis — a campaign that has included an assortment of cursing, accusations of lying and name dropping of New York City Mayor Bill deBlasio, who is unpopular in the district.

While a winner has not been called, Malliotakis is currently leading in votes against Rose, a freshman Democrat, in an area Trump won by 10 points.

However, Malliotakis on Tuesday declared victory, saying that “this race was about the brave men and women of the NYPD and all our law enforcement and first responders." But Rose has not conceded in the race and has called for every vote to be counted.

Virginia's 7th District: Former CIA officer Abbigail Spanberger, part of the blue wave in 2018, was locked in a tight trace with Republican state Del. Nick Freitas, two years after she flipped the seat from red to blue.

As of Wednesday afternoon, Freitas was leading by a few hundred votes after leading by tens of thousands at one point, The race will hinge on absentee ballots yet to be counted.