Rob Quist and his wife in Helena, Montana. Quist is hoping to flip a seat that has been held by Republicans for 20 years. AP Photo/Bobby Caina Calvan

The Democratic Party is hoping to ride a wave of anti-Trump fervor to win back control of the House in the 2018 midterms.

But several unexpectedly close contests in the coming months could foreshadow how difficult it will be to overcome Republicans' 44-seat majority.

Democrats are intensely watching four special elections that begin this week for House seats vacated by lawmakers who joined President Donald Trump's administration. The first comes Tuesday in Kansas to replace Mike Pompeo, now the director of the CIA.

In the wake of a disastrous 2016 election cycle, Democratic Party leaders pledged to compete harder in state and local races, even in solid-red states.

Democrats involved in the races who spoke with Business Insider acknowledged that all the races would be difficult — three of the four seats have been held by Republicans for decades.

But party leaders are encouraged by polling in Georgia and Kansas, as well as an energized party base that has organized protests, flooded Congress with calls, and helped organizations like the American Civil Liberties Union smash fundraising records.

"These congressional districts have been ruby red for decades, and the fact that we are even discussing potentially competitive races here demonstrates the power of the grassroots and marks a big problem for House Republicans," said Meredith Kelly, the communications director for the Democratic Congressional Campaign Committee.

Republicans are taking the threat of upset victories in some seemingly safe districts seriously.

A Republican operative familiar with the races said a major concern for the GOP was that the party's base could be complacent after Trump's victory.

"The energy we've seen, there's been a slight downtick, which I think is natural coming off a very contentious election that we won," the operative told Business Insider.

The operative added that the liberal opposition to Trump was "energized from the get-go" and would be out in full force for these upcoming elections. Republicans will have to ensure their base is, as the operative said, "reengaged."

Jesse Hunt, a spokesman for the National Republican Congressional Committee, told Business Insider the races would hinge on "making sure Republican voters understand what is at stake in all of these elections and they get out to vote."

"In an April special election, turnout is critical," Hunt said.

But turning out voters in high numbers may prove difficult. Hunt said the NRCC was heavily focused on "making sure those voters know when that vote is taking place."

What's the matter with Kansas?

In the first of this year's special elections, Republicans have found themselves playing last-minute defense.

Kansas Democrats had considered the race for the seat formerly held by Pompeo in the state's 4th Congressional District to be a long shot — most polling before this week showed that Republican Ron Estes was the overwhelming favorite to win the Tuesday election over Democrat James Thompson.

But recent polling has shown a much tighter race than expected.

The DCCC on Monday announced its first investment: 25,000 live get-out-the-vote calls to Democrats and independents in the district on behalf of Thompson, an attorney and US Army veteran.

Republicans appeared concerned, too, buying TV ads in the state for Estes, the state treasurer, and dispatching Texas Sen. Ted Cruz to Wichita to stump for him. On Monday, Trump himself recorded a robocall that went out to voters in the district.

"Republican Ron Estes needs your vote and needs it badly," Trump said in the call. "Our country needs help. Ron is going to be helping us, big league."

Ron Estes, the Republican running in Kansas' 4th Congressional District. AP Photo/Orlin Wagner

Last year, Pompeo crushed his opponent, Democrat Daniel Giroux, 60% to 30%. The district has been under Republican control since 1995, and no Democrat has won a House election there since 1992.

Thompson, who has tied himself closely to Sen. Bernie Sanders of Vermont, clashed with the state party after it declined to give his campaign $20,000, according to The Wichita Eagle. The state party said it did not have the necessary funding to provide him — it has limited funds and hopes to compete in other state districts in 2018.

But Thompson made up some of the difference on his own.

In the final days of the campaign, the attorney saw a substantial increase in fundraising. Thompson raised roughly $240,000 from 20,000 individual donations since late last week, The Huffington Post reported. The Democratic National Committee also jumped into the race at its tail end, sending robocalls recorded by Vice Chair Michael Blake.

All eyes on Georgia

The story in Georgia's 6th Congressional District — where Trump's secretary of health and human services, Tom Price, held his House seat — is Democratic candidate Jon Ossoff and his massive fundraising effort.

In three months, the 30-year-old documentary filmmaker and former congressional aide has raised a whopping $8.3 million, vastly more than most candidates running in major statewide races. Ossoff's fundraising haul was more than any member of Congress had raised over a two-year period since 2012 other than House Speaker Paul Ryan and former House Speaker John Boehner.

Although Democrats haven't won this House seat since 1976 — it was occupied for 20 years by former House Speaker Newt Gingrich — Democrats and Republicans view it as the most competitive race among the four special elections.

"You see $8.3 million, that's a significant chunk that somebody can run in their district," said one GOP operative familiar with the race. "Essentially, that's what somebody usually raises for a statewide campaign, not an off-year, early special election."

The operative added that he hadn't seen anything resembling that level of fundraising in past special elections.

"It is a large amount of money from out-of-state donors who are clearly very fired up about opposing Donald Trump," he said. "That's very clear. The liberal base dislikes Donald Trump."

In addition to being well-funded, Ossoff is also heavily staffed. The DCCC sent eight staffers to Georgia in March to help his election efforts, bringing his total to 70 paid staffers and 2,000 volunteers. The DNC's bylaws mandate that the organization stay neutral during the primary, but the committee is prepared to deploy staffers and high-profile surrogates to the district for Ossoff if he finds himself in a head-to-head runoff.

Another layer to this election is the sheer number of candidates running — 11 Republicans and five Democrats. All candidates run on one ballot for the special election, which is April 18. If no candidate clears 50%, the top two will participate in a runoff election on June 20.

Jon Ossoff, the Democratic candidate for Georgia's 6th Congressional District. AP Photo/John Bazemore

With deep pockets funded overwhelmingly by out-of-state liberal donors eager to score a Trump-inspired victory, Ossoff is the most recognized Democrat, but many of the Republicans on the ballot have done little to separate themselves from the others.

"Not only is it a special election, but in Georgia it's a 'jungle primary,' where you have a dozen Republican candidates and you really only have one Democratic candidate because he's consolidated all of the support," the GOP operative said, adding that he believed the candidate's "floor" was a percentage in the mid-to-high 40s.

"For all intents and purposes, he's the only Democrat running," he said. "With all of that money to be put into ads, he's the only one they're hearing about."

In last fall's election, Price beat his Democratic challenger, Rodney Stooksbury, 62% to 38%. But Democrats are hoping that antipathy toward Trump, who won the state by a slimmer 51%-to-46% margin, can help turn the tide in the district.

A WXIA-TV Atlanta/SurveyUSA poll in early April showed Ossoff well ahead of the field with 43% support, while the highest-polling GOP candidate, former Georgia Secretary of State Karen Handel, registered at 15%.

Another poll showed that in a head-to-head matchup, Ossoff would hold a 42.4%-to-41% advantage over Handel, whose polling would jump with consolidated GOP support behind her.

Republicans have attempted to paint Ossoff as a "far left" candidate who would be more loyal to House Minority Leader Nancy Pelosi — an unpopular name in the district — than to local voters. Republicans have pushed a series of ads claiming that Ossoff misrepresented some of his past foreign-policy experience while working on Capitol Hill.

Republicans are making a larger investment in the Georgia race than in the other three races.

"We're obviously monitoring all of it closely, some closer than others," the GOP operative said. "We've obviously made a greater investment in Georgia than we have in Montana or Kansas, and then South Carolina as well."

On to Montana

Though he has stayed on the sidelines of this month's contests, Sanders told The Huffington Post this week that he would campaign in May for another unconventional candidate attempting to replicate the senator's grassroots style of populism: the folk singer Rob Quist.

Running on a promise to protect public lands and lobby for affordable health insurance, Quist is hoping to flip a seat that has been held by Republicans for 20 years, in a state that voted overwhelmingly to elect Trump.

Quist's campaign has downplayed the party association, instead focusing on local issues and attempting to cast his opponent, multimillionaire Greg Gianforte, as a plutocrat — a tactic that proved successful in the 2016 gubernatorial race against Democratic Gov. Steve Bullock.

"Montanans roundly rejected Greg Gianforte back in November for being out of touch, and given the chance, they'll do it again," said Tina Olechowski, a spokeswoman for Quist.

The national Democratic organizations have largely stayed out of the race. The Huffington Post has reported that the DCCC likely views the race as a lost cause, citing the organization's refusal to run ads in the state.

Two Democratic sources familiar with the DCCC's and the campaign's thinking said the party was hoping to deploy high-profile surrogates to the district as the race winds down. These people said the folk singer was hoping to cast himself as an outsider regardless, focusing on local issues rather than running to oppose Trump.

'Make America America Again' in South Carolina

The race in South Carolina's 5th District is not as favorable for Democrats — many officials acknowledged privately that the June 20 contest was a major uphill battle. Most analysts have written it off entirely.

Democrat John Spratt held the district until 2010, when the Tea Party wave swept Mick Mulvaney, now the director of the Office of Management and Budget, into office. Redistricting in 2012 helped it trend further red — Trump won the 5th by over 18 points, and Mulvaney won reelection by 20 points.

The presumed Democratic frontrunner is Archie Parnell, a senior Goldman Sachs adviser who was a former Capitol Hill and Department of Justice staffer. Republicans are painting themselves as Trump-style outsiders — former Republican Party Chairman Chad Connelly has praised Trump, while Sheri Few's campaign slogan is "Make America America Again."

Still, state Democrats are encouraged by the months of aggressive grassroots demonstrations of resistance to Trump's agenda. They're hoping Ossoff wins without a runoff, signaling a potential Democratic wave with the help of more volunteers, money, and attention.

"Ever since millions of Americans came out for the Women's March, it has been clear that people in every part of the country have serious concerns with the direction that Donald Trump and congressional Republicans are taking the country," said Matthew Ellison, a spokesman for the South Carolina Democratic Party. "Voters are eager to register those concerns at the ballot box at first opportunity. If Washington Republicans continue pursuing policies to benefit themselves and their donors while harming everybody else, no Republican seat will be safe."

Parnell got a boost from Democratic presidential nominee Hillary Clinton's campaign manager, Robby Mook, who sent an email Monday on behalf of the South Carolina candidate.

"My start in politics was as grassroots as you can get: campaigning for Democrats at the town dump," Mook wrote in the email, according to Politico Playbook. "Archie Parnell is running for the seat that John Spratt held when I first started working on congressional campaigns, a seat that Democrats had held for over a century."