A season of raucous primary elections appears likely to feature another big night on Tuesday, after President Donald Trump tossed a grenade into a Republican vs. Republican race with the surprise endorsement of a far-right candidate hoping to overthrow a sitting governor.

“Kris Kobach, a strong and early supporter of mine, is running for Governor of the Great State of Kansas,” Trump wrote in a tweet sent Monday afternoon. “He is a fantastic guy who loves his State and our Country - he will be a GREAT Governor and has my full & total Endorsement! Strong on Crime, Border & Military.”

Kobach, the Kansas secretary of state, is hoping that his hardline immigration views and a crowded field—there are seven Republican candidates—will be enough to overcome financial shortfalls and a cozy history with white supremacists. Kobach, as well as five other Republican challengers, is aiming to ride Trump-style anti-establishment fervor to unseat current Republican Gov. Jeff Colyer.

Elsewhere in the Wheat State, Democrats are jockeying in an effort to peel off some of the state’s Republican-held seats, including Kansas’ 3rd Congressional District, which includes Kansas City and which Hillary Clinton won by a single point in 2016.

Republican Rep. Kevin Yoder currently represents the district, and a diverse group of Democrats is competing to topple the four-term congressman, including lawyer Brent Welder, beneficiary of the double-barrel progressive endorsement of Alexandria Ocasio-Cortez and Sen. Bernie Sanders (I-VT). Sharice Davids, a former mixed martial arts fighter backed by EMILY’s List who would make history as the first openly lesbian Native American woman ever to serve in Congress, is also running for the nomination.

In the state’s 4th Congressional District, civil rights attorney James Thompson, another beneficiary of the combined Sanders/Ocasio-Cortez endorsement, is running again after coming up short in 2017 in a surprisingly close race for this seat, which was vacated after Mike Pompeo became director of the Central Intelligence Agency.

In Ohio, the nation’s last special congressional election pits Franklin County Recorder Danny O’Connor against Republican state Sen. Troy Balderson. An election to replace outgoing Rep. Pat Tiberi, who resigned to lead the Ohio Business Roundtable, was supposed to be a breeze for the Republican Party—the seat hasn’t gone Democratic since 1939, save for a brief two-year term starting in 1981—has turned into a coin flip.

Trump recently swooped into the district, which stretches from Zanesville in the east to the edge of Richland County north of Columbus, to help rally the troops for Balderson on Saturday night. While the practical significance of the contest is minimal—either man would serve until November, at which point they’d be in an election contest again against each other—the symbolic ramifications of the race are enormous, particularly for the Republican Party.

There is deep concern that even a narrow victory for Republicans in the 12th District, from which Gov. John Kasich hails, would portend a very challenging environment for the GOP in November, especially in districts that include similar wealthy and educated suburban voters who may be beginning to turn away from the president.

O’Connor, like Conor Lamb, the last Democrat to pull off such an upset in western Pennsylvania earlier this year, has attempted to present himself as an independent with a specific eye on protecting Social Security and Medicare. Republican groups, which have injected millions into the race, have strayed from a strictly economic message in recent weeks in favor of ads tying O’Connor to House Minority Leader Nancy Pelosi (D-CA) and the broader “Resistance.”

In Michigan, the marquee matchup on Tuesday pits three Democrats against each other in the gubernatorial primary in Michigan, where polling suggests the winner has a shot at taking back the governorship in November. Former state senator Gretchen Whitmer has led in most polling, but Abdul El-Sayed, a Muslim-American doctor running on Medicare for All and a set of leftist platforms, has gained some momentum in recent weeks with large rallies featuring Ocasio-Cortez and Sanders. Shri Thander is also in the mix but viewed with deep skepticism by some liberals, who question his progressive credentials.