After all the votes are counted, Democrats will emerge from the first midterm election of Donald Trump's presidency with their narrowest majority in the House of Representative since 1945.

If current results hold, Democrats will control 229 seats, a net gain of 36, compared with 206 for Republicans, giving them a majority of 11 seats. Democratic candidates won, or are currently leading in, 18 seats by a margin lower than 5 percentage points.

While the party did succeed in retaking the House, their efforts fell well short of historical trend lines recorded in previous wave elections.

The Democrats' net gain of 36 seats pales in comparison to the Tea Party wave of 2010, when Republicans captured 63 seats in the House. The GOP's post-2010 majority of 24 seats was more than double the amount that Democrats are expected to possess from 2019 to 2021.

Furthermore, the Democrats' majority this January will be smaller than that which the party held from 2007 to 2009, the last time they took power and elected Nancy Pelosi (D., Calif.) as House speaker. Democrats now have their narrowest majority in the House since the 1943 to 1945 Congress, when only four seats separated the two parties from the speaker's gavel.

On election night, the Democrats' majority ran through a number of districts that Trump carried on his way to the White House in 2016. As noted by the Cook Political Report, however, Democrats struggled to win seats in districts where the president captured more than 55 percent of the vote.

Democratic candidates emerged victorious in areas as geographically diverse as Iowa's 1st and 3rd districts, as well as New York's 19th and 22nd districts.

Although Trump carried both districts in the Hawkeye State by a margin of 3.5 percentage points, Democrats Abby Finkenauer and Cindy Axne won closely contested victories over Republican incumbents.

Iowa's first district voted for Obama in 2008 and 2012 before flipping to Trump. Democratic representative Bruce Braley held the seat from 2007 to 2013, before now-defeated incumbent Rod Blum flipped it in 2014. Finkenauer performed well in the district's urban counties, outpacing Blum's ability to make up the difference in more conservative areas. She also out-raised Blum with help from outside money, which accounted for most of her campaign's funds.

Tim Busch, chair of the Benton County, Iowa Republicans, pointed to Finkenauer's performance in urban districts and fundraising advantages as helping her secure a victory, but added that the Republican Party could win back the district.

"I suspect that if the GOP puts up a credible candidate she could easily be a one-term representative," Busch told the Washington Free Beacon.

Similarly, New York's 19th district voted twice for Obama before turning to Trump. Antonio Delgado, the Democratic challenger, ran up his vote total in the district's progressive base, while turnout in the rural counties was not enough to push incumbent John Faso ahead.

Democrats also underperformed in districts that were considered fertile territory for the party.

If current vote totals hold, Democrats and Republicans will split California's 10th, 25th, 39th, 45th, 48th, and 49th districts, all of which were competitive districts won by Hillary Clinton in 2016.

Republican incumbents Jeff Denham and Mimi Walters narrowly held on to their seats, while Young Kim defeated Democrat Gil Cisneros to become the first Korean-American woman in Congress in the 39th District.

Republican incumbents Steve Knight and Dana Rohrabacher were defeated, however, and Diane Harkey lost to her Democratic challenger in California's 49th, a seat held by Darrell Issa.

Democrats also made inroads in deeply conservative districts that will be difficult to hold in 2020 when the party is playing defense and Trump is on top of the ballot to spur GOP turnout.

In South Carolina's First Congressional District, first-time Democratic candidate Joe Cunningham edged out Republican Katie Arrington by slightly over 1 percentage point to carry the seat. The race took on national dimensions when Arrington, endorsed by Trump, ousted incumbent congressman Mark Sanford in the Republican primary.

The seat, which includes parts of Charleston and the majority of South Carolina's coast, has been in Republican hands since 1981. Cunningham was able to secure a narrow victory by capitalizing on the GOP primary scuffle, as exhibited by the endorsements his campaign garnered from several local Republicans. He also led Arrington in fundraising—$1.9 million to $1.3 million, according to the Center for Responsive Politics. Nearly a third of Cunningham's contributions came from outside South Carolina.

The crossover support, a strong showing in urban Charleston County, and Cunningham's fundraising lead were enough to push him over the finish line on Election Day.

Likewise, in Oklahoma's Fifth Congressional District, Democrat Kendra Horn ousted incumbent Republican congressman Steve Russell by 1.4 percent of the vote. The district, covering Oklahoma City and its suburbs, has reliably elected Republicans since 1975. The Democrat, however, was able to disrupt that trend in part because of outside spending and higher-than-normal turnout in the district's urban core.

Horn, a political newcomer, led the three-term incumbent—pulling in $1 million to Russell's $900,000—for most of the race. She also benefited from a $400,000 ad buy from Independence USA, a super PAC affiliated with former New York City mayor Michael Bloomberg, in the closing weeks of the campaign.

Despite her upset victory, Horn is viewed as an underdog should she seek reelection in two years, especially as Trump carried the district by 13 points.

"Some of the seats the Democrats won, particularly those in places where the president won by double-digits in 2016, will be difficult to hold," said Kyle Kondik, managing editor of Sabato's Crystal Ball. "That said, some of them, particularly those that voted for Hillary Clinton in 2016, probably won't be that hard to hold, at least while Trump is in the White House."

"The 2020 House map will shift—Republicans may be able to focus more heavily on some Trump-won seats won by Democrats this year or ones that Democrats have held for multiple cycles, while Democrats may spot some new opportunities in changing places, like suburban Texas," Kondik added.

On election night, Pelosi attempted to appease both her party's progressive base and the crossover voters necessary to maintain her hold on power.

"Today is more than about Democrats and Republicans," Pelosi said in her victory remarks. "It's about restoring the Constitution's checks and balances to the Trump administration."

"We will strive for bipartisanship, with fairness on all sides," Pelosi added. "We will have a responsibility to find our common ground where we can [and] stand our ground where we can't, but we must try."

While there is no debate that a Democratic House majority will serve as a check on Trump's agenda for the next two years, it is also clear that Republicans are well within striking distance of retaking control in 2020.