Primary and special election results across five states Tuesday raised concerns about the prospect of Republicans holding their House majority while setting the stage for some of the country's most important races for Senate and governor. The most closely watched contest took place in Ohio, where the 12th District special election was too close to call as Republicans declared victory for GOP state Sen. Troy Balderson. Democratic candidate Danny O'Connor mounted a strong challenge for a seat that Republicans have held for more than three decades in a district which President Donald Trump won by about 11 percentage points. The result made Democrats optimistic about their prospects in the roughly 60 GOP-held districts with a less Republican lean than Ohio's 12th District.

Elsewhere, voters in Missouri picked the nominees for one of the most competitive Senate races of the cycle, where Democratic Sen. Claire McCaskill will fight for her political life in November. A divisive Trump ally was also locked into a tight GOP primary fight for the Kansas governor nomination. On Wednesday, nonpartisan elections analysis sites moved ratings for several GOP-held seats in states which held primaries Tuesday in favor of Democrats. Cook Political Report moved both Kansas' 2nd and 3rd Districts to "toss-up" from "lean" Republican, and shifted Washington's 3rd District to "lean" Republican from "likely" Republican. Cook tweet Sabato's Crystal Ball changed its ratings for Kansas' 3rd District to "toss-up" and Washington's 3rd District to "leans" Republican, as well. It also moved Michigan's 11th District to "leans" Democrat from "toss-up" and Washington's 5th District to "toss-up" from "leans" Republican. Kondik tweet Cook also moved Ohio's 12th District to "lean" Republican from "toss-up." Here are some of Tuesday's notable results:

Kansas

In the potentially competitive gubernatorial race in Kansas, Trump-backed Kansas Secretary of State Kris Kobach and incumbent Gov. Jeff Colyer were deadlocked in the Republican primary on Wednesday morning as final votes were counted. In a dynamic familiar to this year's primary cycle, both candidates fought to be seen as the most loyal ally of the president. Kobach received Trump's endorsement just a day before the election and had a very small lead in a still undecided contest. Republican Party leaders worry that Kobach, a polarizing conservative who imitates the president's inflammatory style and takes a tough stance on immigration, would energize Democrats and undermine the GOP's prospects in the November general election. He served on the commission investigating the president's unfounded claims of widespread voter fraud, which Trump shut down at the start of the year. Democratic state Sen. Laura Kelly won her party's gubernatorial primary. In Kansas's competitive 3rd House District, Sharice Davids was leading a still undecided Democratic primary. Brent Welder, a candidate backed by Sen. Bernie Sanders, I-Vt., who cast himself as the more progressive option, was trailing. The winner will try to unseat GOP Rep. Kevin Yoder. In the state's 2nd District, which includes the capital city of Topeka and the liberal college city of Lawrence, GOP Rep. Lynn Jenkins retired, leaving Republicans without an incumbent in a district that could swing left. Paul Davis, a former lawmaker who failed to take the governor's seat in 2014, won the Democratic nomination. He will face Republican former Army officer Steve Watkins in the general election.

Michigan

Michigan Democrat Gubernatorial candidate Gretchen Whitmer addresses the 37th United Auto Workers Constitutional Convention June14, 2018 at Cobo Center in Detroit, Michigan. Bill Pugliano | Getty Images

Former Michigan state Sen. Gretchen Whitmer won the Democratic primary for governor Tuesday and will face Republican Attorney General Bill Schuette in the general election. Whitmer beat Abdul El-Sayed, a Sanders-backed newcomer who billed himself as the race's progressive option. Democrats aim to reclaim control in a state that the president only narrowly won in 2016. In the race for the Republican nomination for Senate, former combat veteran John James beat out Sandy Pensler, a financial executive, after receiving the president's endorsement late in the race. James will face Democratic Sen. Debbie Stabenow, one of 10 Democrats running this year in a state Trump carried in 2016. An early poll of the potential general election matchup showed the incumbent with a comfortable edge over James.

Democrats pick former Michigan state Rep. Rashida Tlaib to run unopposed for the congressional seat that former Rep. John Conyers held for more than 50 years. Al Goldis | AP

Democrat Rashida Tlaib won a race to run unopposed for the deeply blue 13th Congressional District vacated by fellow Democrat John Conyers, putting her on track to become the first Muslim woman in Congress. Michigan voters also set the stage for two House races that should be competitive in November. Democratic former Defense Department official Elissa Slotkin will face off against Rep. Mike Bishop in the 8th District. In the 11th District — vacated by GOP Rep. Dave Trott's retirement — Democratic former Obama administration official Haley Stevens and Republican businesswoman Lena Epstein led their still undecided primary contests.

Missouri

In Missouri, Republican Attorney General Josh Hawley easily won his primary to face McCaskill in November. The result sets up what should be one of the most important — and nasty — Senate contests in 2018.

Missouri Attorney General Josh Hawley John Sleezer | Tribune News Service | Getty Images

McCaskill, one of the most vulnerable members of the chamber, runs for re-election in a state Trump won by nearly 20 percentage points. The contest is among a handful that will determine whether Republicans can keep or expand their 51-49 seat majority in the Senate. Cori Bush, a first-time Democratic House candidate who tried to pull an upset reminiscent of Alexandria Ocasio-Cortez's triumph over high-ranking Democratic Rep. Joe Crowley, failed to overcome Rep. William Lacy Clay in Missouri's blue 1st District.

Ohio

The 12th District special election was too close to call as of Wednesday morning as Balderson led O'Connor by less than a percentage point. The Republican appeared to have an inside track to victory, pending the count of provisional ballots and a potential mandatory recount. Still, the nail-biting result in a district that the GOP last lost in 1980 is hardly assuring for the party. Read more about the Ohio race here.

Washington

In Washington state, voters picked their nominees in a couple pivotal House races. In the toss-up 8th District, Republican state Sen. Dino Rossi advanced to the general election in the state's top-two primary system. Democratic physician Kim Schrier had a slight edge over lawyer Jason Rittereiser for the second spot. Democrats also hope to mount a strong challenge to high-ranking Republican Rep. Cathy McMorris Rodgers in the state's 5th District. She advanced to the general election along with Democratic former state lawmaker and educator Lisa Brown, winning the primary by less than 1 percentage point. That margin led some observers to raise concerns about the Republican incumbent's ability to get re-elected. Correction: Josh Hawley is attorney general of Missouri. An earlier version misstated his title.

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