It was the biggest primary night since Super Tuesday, and there were few surprises in the results.
Bernie Moreno won the Republican Senate primary in Ohio, wielding the powerful endorsement of former President Donald J. Trump to become the Republican nominee in perhaps the most consequential race in the battle for the Senate this November.
Three incumbent representatives also fended off primary challenges in Illinois, and the results of a special primary in California will, eventually, decide who completes the term of former House Speaker Kevin McCarthy, who was ousted from his post last year and left Congress not long after.
Here are four takeaways.
With the power of Trump, Moreno prevails in Ohio.
Bernie Moreno, a wealthy former car dealer and political newcomer, emerged victorious from a three-way brawl in the Ohio Republican primary to determine who would take on Sherrod Brown, the Democratic incumbent, in an increasingly Republican state.
The hotly contested primary proved once again just how powerful an endorsement from Mr. Trump is, especially in a state like Ohio. The former president backed Mr. Moreno early, while the Republican establishment tried mightily to lift its chosen candidate, Matt Dolan, a wealthy state senator.
But the star power of Ohio’s Republican governor, Mike DeWine, and its former moderate senator, Rob Portman, was decisively outshone by Mr. Trump. Mr. Moreno cruised to victory, earning a narrow majority of the vote in a three-way race.
Democratic and Republican incumbents claim victory in Illinois.
Three incumbent representatives in Illinois — two Democrats and a Republican — faced significant challengers in Tuesday’s primary, and all three congressmen survived — demonstrating the power of incumbency.
Representative Danny Davis won by a wide margin in the Democratic primary for the Seventh Congressional District. He has represented a swath of Chicagoland for nearly 28 years. He is also 82 years old, and faced a number of younger opponents who were ultimately swept aside after the Democratic establishment in Illinois rallied around Mr. Davis.
Representative Jesús García, a progressive Democrat known as Chuy, won by a wide margin in the Democratic primary in the Fourth Congressional District in Chicago, beating his opponent, Raymond Lopez, in a landslide. The race was fought in part over immigration issues. Mr. García, who has called himself a “proud immigrant,” criticized President Biden when he referred to an undocumented migrant as “an illegal” in his State of the Union speech. Mr. Lopez was more conservative on immigration.
The third incumbent, Representative Mike Bost, won his Republican primary in the 12th Congressional District. Here, Mr. Trump again became a factor. Mr. Bost is nobody’s idea of a moderate Republican, and had Mr. Trump’s endorsement, but he was nevertheless challenged from his right by Darren Bailey, an ardent pro-Trump Republican who lost the governor’s race to J.B. Pritzker by a wide margin in 2022.
Mr. Bailey claimed to be the true avatar of Mr. Trump’s movement, but Mr. Bost ultimately edged out Mr. Bailey.
Kevin McCarthy’s seat remains in limbo.
Vince Fong, a Republican state assemblyman, advanced in a special primary in California to complete the term of Mr. McCarthy, a Republican who was ousted from his role as speaker of the House and resigned soon after.
Mr. Fong did not hit the 50 percent threshold to avoid a runoff, and two other candidates were running close for second place, with votes still outstanding: Mike Boudreaux, another Republican and the Tulare County sheriff, and Marisa Wood, a Democrat and teacher. The runoff election is scheduled for May 21.
Mr. Fong and Mr. Boudreaux advanced in a separate primary held on Super Tuesday for a full term in the seat starting January 2025.
Trump and Biden notched huge victories, as expected.
Mr. Biden and Mr. Trump, the presumptive presidential nominees of their parties, swept to near-total victories in the states that held primaries on Tuesday: Arizona, Florida, Illinois, Kansas and Ohio.
But the results still reflected a small but significant resistance in each party to their presumptive candidates.
Mr. Trump achieved overwhelming margins of victory, winning at least 75 percent of the vote in every state as of early Wednesday. Nikki Haley, who dropped out of the race after Super Tuesday, took notable minorities of the vote in each primary. Her best showing was in Arizona.
Mr. Biden took an even larger percentage of the vote in the Democratic primaries, winning at least 83 percent of the vote in each state as of early Wednesday. But some voters still registered their discontent with his candidacy. In Ohio, 13 percent voted for Representative Dean Phillips, who dropped out and endorsed Mr. Biden after Super Tuesday. In Kansas, more than 10 percent voted for the “none of the names shown” ballot option.