Washington (CNN) The Ohio special election for a House seat that's been in Republican hands for three decades was too close to call Tuesday night.

But that it was close at all shows just how daunting the political landscape facing Republicans is headed into November's midterm elections.

Republicans spent millions of dollars to avoid an embarrassing loss, and President Donald Trump visited the district just days before the election. With early and election day votes counted, Republican Troy Balderson has a 0.9-percentage-point edge over Democrat Danny O'Connor, with absentee and provisional ballots remaining.

The other closely watched race where Trump was involved, the Kansas GOP gubernatorial primary, continued into the early Wednesday morning hours. The result there will be a test of Trump's endorsement and should Kansas Secretary of State Kris Kobach prevail, Democrats believe they could win in the deep-red state (Note: We'll update this piece as results are finalized).

Here are four early takeaways from Tuesday's Ohio special election and primaries in Kansas, Michigan, Missouri and Washington.

1. It's time for Republicans to panic about the House

The neck-and-neck race in a ruby red Ohio district was the latest evidence that the Republican majority in the House is in peril.

Why? Look at the makeup of the district. Trump in 2016 and Mitt Romney in 2012 each won there by 11 percentage points. There are 68 Republican-held House districts that are more favorable for Democrats, per the Cook Political Report's "Partisan Voter Index," which factors in recent election results -- and Democrats only need a net gain of 23 seats to take control.

Then, consider the turnout. Voters in urban and suburban portions of the district voted at much higher rates than those in its rural, largely pro-Republican areas.

The bottom line: Democratic voters are energized, the suburbs are swinging in their favor and Republicans are sitting elections out. If the GOP can't undo that massive enthusiasm gap by November, its House majority is in serious jeopardy.

Signs of panic were evident Tuesday night. Corry Bliss, the executive director of the GOP-aligned Congressional Leadership Fund, issued a statement warning Republicans that his super PAC can't swamp Democrats in spending in every district, as it did in Ohio.

"While we won tonight, this remains a very tough political environment and moving forward, we cannot expect to win tough races when our candidate is being outraised. Any Republican running for Congress getting vastly outraised by an opponent needs to start raising more money," he said.

What Bliss is warning about is a big problem. Per a CNN analysis, an eye-popping 55 Democratic challengers outraised the Republican incumbents they are facing.

Late into the night, Republicans were watching as yet another reason to worry emerged: In Washington state, the leading Republicans in three GOP-held districts were all being held under 50% of the vote in the state's jungle primary, where Democrats and Republicans compete in the same contest and the top two finishers advance. It could foreshadow trouble for those candidates in the fall.

2. Still waiting in Kansas

Jeff Colyer, left, and Kris Kobach

Kobach was in a dead heat with incumbent Gov. Jeff Colyer in the Republican gubernatorial primary there.

Johnson County, the heavily populated suburbs of Kansas City, had yet to fully report early into Wednesday morning. There's still enough outstanding vote left to count there that could determine the outcome of the contest.

Its results were likely to swing the race.

A loss by Kobach -- who is controversial because he advocates restrictive voting laws and has backed Trump's false claims of widespread voter fraud -- would be an embarrassment for Trump, who has success at picking winners in GOP primaries this year. But it would be a relief for Republicans who see him as a weaker general election candidate.

A Kobach win would underscore Trump's influence among Republican primary voters.

If Colyer wins, he told CNN in an interview Tuesday that some of the credit would belong to former Sen. Bob Dole, who endorsed him.

3. Missouri GOP maneuver backfires

When Missourians gathered more than 300,000 petition signatures to force a referendum on the state's right-to-work law, Republicans who control the state legislature tried to protect the union-busting law with a maneuver they thought would tip the outcome in their favor.

Their move: Put the referendum on the ballot in the August primary, when they expected strong Republican turnout, rather than in the November general election, when they expected pro-union Democrats would show up in full force.

It backfired spectacularly.

Missouri voters rejected the right-to-work law by a 2-to-1 margin -- a remarkable defeat for a Republican priority in a state Trump won by 19 percentage points in 2016.

The result was a major victory for labor unions, which invested $16 million in the campaign. It could also mark a turning point in the Midwest, years after Republicans won battles against unions in states like Wisconsin and Indiana.

"The defeat of this poisonous anti-worker legislation is a victory for all workers across the country," AFL-CIO President Richard Trumka said in a celebratory statement Tuesday night. "The message sent by every single person who worked to defeat Prop. A is clear: When we see an opportunity to use our political voice to give workers a more level playing field, we will seize it with overwhelming passion and determination."

4. Progressive push hits a snag in the Midwest

For progressives hoping for another victory in the mold of Alexandria Ocasio-Cortez's stunning June ouster of Rep. Joe Crowley, Tuesday was a major letdown.

In the night's marquee contest, progressive outsider Abdul El-Sayed fell well short in his bid to upset former state Senate Minority leader Gretchen Whitmer, who won the nomination at a canter and is now poised for a November showdown with Republican Attorney General Bill Schuette.

Ocasio-Cortez and Sen. Bernie Sanders, who defeated Hillary Clinton in the state two years ago and predicted El-Sayed would follow in his path, campaigned for El-Sayed, who ran on an innovative "Medicare for all" plan and the promise of public broadband and tuition-free college.

Whitmer painted the 33-year-old doctor's platform as mostly unrealistic in a state won by Trump in 2016. She also had the backing of New York Sen. Kirsten Gillibrand and most of the state party establishment. The result means the top of Michigan Democrats' ticket will feature two women: Whitmer and incumbent Sen. Debbie Stabenow -- another landmark in what's been a bumper year for female candidates.

Keeping with the mixed-bag theme of the night, former state Rep. Rashida Tlaib is projected to win the general election primary to replace former Rep. John Conyers Jr., while Fayrouz Saad lagged far behind in her contest. Both were endorsed by Ocasio-Cortez. Tlaib is on track to become the first Muslim woman in Congress.

But there was more progressive heartbreak in Missouri, where activist Cori Bush lost in her bid to unseat Democratic Rep. William Lacy Clay despite a visit and the vocal support of Ocasio-Cortez.

It was a split decision in Kansas: labor lawyer Brent Welder failed to beat Sharice Davids in the state's 3rd District, CNN projects, despite Sanders and Ocasio-Cortez's support. However, they rallied in July for James Thompson, who won the 4th District primary Tuesday and secured a rematch of his 2017 special election against GOP Rep. Ron Estes.

Thompson lost that race by less than 7 points a few months after Republican Mike Pompeo won re-election there by more than 30.