WASHINGTON (AP) — With the presidential nominations locked up, the most high-profile election in Ohio’s primary on Tuesday will be the Republican contest to take on Ohio’s Democratic U.S. senator.

There are presidential contests in five states on Tuesday, but Ohio is one of two states also holding state and congressional primaries that day. Democratic Sen. Sherrod Brown, first elected in 2006 and uncontested in his primary this year, is among the most vulnerable members of a closely divided chamber and has managed to hold onto his seat even as the state has shifted to the right. In his most recent reelection in 2018, he defeated then-Rep. Jim Renacci by almost 7 percentage points. Two years later, Ohio voted for then-President Donald Trump by 8 points.

There are three Republicans on the ballot: state Sen. Matt Dolan, Ohio Secretary of State Frank LaRose, and businessman Bernie Moreno. LaRose and Moreno have aligned themselves with the pro-Trump camp of the party, while Dolan is backed by more establishment Republicans, including Gov. Mike DeWine and former Sen. Rob Portman.

Moreno has the endorsements from Trump and the state’s junior senator, JD Vance. Dolan finished third in the 2022 primary that Vance won.

Other notable races are in Ohio’s 2nd, 6th and 9th Congressional Districts. Former Rep. Bill Johnson resigned from the 6th District in January for a job in academia. There are two sets of primaries held concurrently for the seat, one to complete the current term and one to serve the next full term. Two Democrats and three Republicans are running to take this seat, which stretches along the eastern border and includes Youngstown. The Republican primaries in Ohio’s 2nd and 9th Districts are significant because the solidly red 2nd District is open following Rep. Brad Wenstrup’s retirement and the 9th, currently held by Democratic Rep. Marcy Kaptur, is considered a top Republican pickup opportunity in the fall.

Besides the U.S. Senate primary and primaries for each of Ohio’s 15 congressional districts, there are primaries for state House, the state Senate and one state Supreme Court seat.

A look at what to expect on election night:

ELECTION DAY

The Ohio state and presidential primaries will be held on Tuesday. Polls close at 7:30 p.m. EDT.

WHAT’S ON THE BALLOT

PRESIDENTIAL PRIMARY (D): Joe Biden, Dean Phillips. 127 delegates at stake.

PRESIDENTIAL PRIMARY (R): Donald Trump, Chris Christie, Ron DeSantis, Nikki Haley, Vivek Ramaswamy. 79 delegates at stake.

U.S. HOUSE DISTRICT 2 PRIMARY (R): Niraj Antani, Kim Georgeton, Phil Heimlich, Ron Hood, Thomas Hwang

U.S. HOUSE DISTRICT 6 PRIMARY (R): Michael Rulli, Reggie Stoltzfus, Rick Tsai (for both full and partial terms)

U.S. HOUSE DISTRICT 9 PRIMARY (R): Steve Lankenau, J.R. Majewski, Derek Merrin, Craig Riedel

SUPREME COURT PRIMARY (D): Lisa Forbes, Terri Jamison (for term ending Dec. 31)

WHO CAN VOTE

Any registered voter in Ohio may participate. Voters can choose only one party’s primary.

DELEGATE ALLOCATION RULES

There are 127 pledged Democratic delegates at stake in Ohio, and they’re awarded according to the national party’s standard rules. Twenty-seven at-large delegates are allocated in proportion to the statewide vote, as are 17 PLEO delegates, or “party leaders and elected officials.” The state’s 15 congressional districts have a combined 83 delegates at stake, which are allocated in proportion to the vote results in each district. Candidates must receive at least 15% of the statewide vote to qualify for any statewide delegates and 15% of the vote in a congressional district to qualify for delegates in that district.

For Republicans, all 79 delegates are awarded to the winner of the statewide popular vote.

DECISION NOTES

The presidential primaries in Ohio are unlikely to be competitive, as Biden and Trump enter as presumptive nominees and face no major opposition. In both races, the first indications that Biden and Trump are winning statewide on a level consistent with the overwhelming margins seen in most other contests held this year may be sufficient to determine the statewide winners.

Be careful about making assumptions about early returns. The first vote updates from Ohio counties usually include votes cast before election day, either in person or by mail. As a result, these initial results might not reflect the final outcome.

The AP does not make projections and will declare a winner only when it’s determined there is no scenario that would allow the trailing candidates to close the gap. If a race has not been called, the AP will continue to cover any newsworthy developments, such as candidate concessions or declarations of victory. In doing so, the AP will make clear that it has not yet declared a winner and explain why.

WHAT DO TURNOUT AND ADVANCE VOTE LOOK LIKE

Turnout in the 2022 Ohio primaries was about 8% of registered voters. There were 7.9 million voters registered in Ohio as of June 16, 2023. The state does not register voters by party.

As of Thursday, nearly 312,000 ballots had been cast before Election Day, about 55% in the Republican primary and about 43% in the Democratic primary. In 2022, pre-Election Day voting made up about 41% of the total votes cast in the primary elections.

HOW LONG DOES VOTE COUNTING USUALLY TAKE?

In the 2022 Republican primary for U.S. Senate, the AP first reported results at 7:38 p.m. ET, or eight minutes after polls closed. The election night tabulation ended at 1:14 a.m. ET with about 99% of total votes counted.

ARE WE THERE YET?

As of March 19, there will be 118 days until the Republican National Convention in Milwaukee, 153 days until the Democratic National Convention in Chicago and 231 days until the November general election.

___

Associated Press writer Robert Yoon contributed to this report.