Ohio voters will go to the polls in less than a week for the Republican Senate midterm primary election, which will be the first major test of former President Donald Trump’s endorsement power.

The state has shifted to the right in recent elections, and as the race to fill the seat vacated by retiring Ohio Republican Sen. Rob Portman heats up, many GOP candidates are attempting to out-Trump one another in the hopes of appealing to the former president’s large following in the state.

Trump threw his support behind venture capitalist J.D. Vance, best known for his book “Hillbilly Elegy,” in a late-term endorsement earlier this month, upending the race. The former president referred to Vance as “an America first warrior” during a campaign rally in Delaware, Ohio, over the weekend.

Trump told the crowd, “He believes so much in making our country great again, and he’s going to do a job on these horrible people that we’re up against.”

The endorsement is a political risk for Trump, who has tried to position himself as the GOP’s kingmaker with varying degrees of success. Vance has consistently trailed Josh Mandel and Mike Gibbons in polls, both of whom have run campaigns touting their own commitments to Trump’s “America First” policies.

On a national level, some of Trump’s early campaign supporters have failed to deliver victories for him. Trump even went so far as to withdraw his endorsement of Alabama Senate candidate Mo Brooks after Brooks’ poll numbers dropped and he stated that it was time to focus on Trump’s false claims that the 2020 election would be rigged.

A victory for Vance in the primary next week could demonstrate the power of Trump’s endorsement. It’s given the candidate a new lease on life as he heads into the final stretch of his primary campaign.

Some supporters who waited in line to see Vance in Ohio on Saturday said Trump’s endorsement convinced them of Vance’s candidacy.

Candidates who did not receive Trump’s endorsement in Ohio are now clinging to voters like McNutt, hoping to portray themselves as the best candidate to advance a Trump-style agenda, even if Trump does not see it.

On Friday, Republican presidential candidate Jane Timken spoke to a crowd of supporters near Cleveland, touching on a number of Trump talking points, including school choice, immigration, and the economy. Trump had previously endorsed Timken for the state party’s leadership position, but not for the Senate race. She described his support for Vance as “disappointing.”

Former Ohio Treasurer Josh Mandel has been campaigning in churches, pitching religious conservatives on “Judeo-Christian values,” which he sees as the foundation of the “America First” movement. Mandel was branded “Pro-God, Pro-Guns, Pro-Trump” at his event, according to campaign signs.

The race has been divisive. Mandel and Gibbons almost got into a fistfight during one of the debates. Mandel shrugged it off, calling himself a “fighter” for conservative values, and he pushed back when asked about his rhetoric, which included a Twitter poll asking his followers whether “Muslim Terrorists” or “Mexican Gangbangers” commit more crimes.

However, in Grove City, 100 miles from Mandel’s Cincinnati event, some voters believe the party needs to refocus.

Only one of the candidates in the race is willing to abandon some of Trump’s most divisive positions. When asked if it was time for Trump to move on from the 2020 election, state Sen. Matt Dolan was the only candidate to raise his hand on a debate stage earlier this month.

Dolan believes his fellow candidates are taking the “wrong approach” by focusing on the 2020 election. He stated that he was not seeking Trump’s endorsement.

The Republican candidate who wins the Senate primary on Tuesday will almost certainly face Democratic frontrunner Tim Ryan in the general election.