An endorsement in the race for next year’s Republican nomination for U.S. Senate has the potential to shake up the field.

Ohio Sec. of State Frank LaRose has led in primary polls among candidates hoping to challenge incumbent Democrat Sherrod Brown, who is seeking a fourth term.

However, on Tuesday, former President Donald Trump announced his backing of a different candidate for the Republican nomination.

Trump announced his support of Bernie Moreno, a Cleveland businessman, in a post on his social media network, Truth Social, Tuesday.

“Bernie Moreno, a highly respected businessman from the GREAT State of Ohio, is exactly the type of MAGA fighter that we need in the United States Senate,” Trump wrote. He said Moreno would “always stand up to the Fascist ‘nut jobs’ and the spineless RINOS” and is the “successful political outsider” needed to defeat Brown, whom he labeled a “Liberal career politician.”

State Sen. Matt Dolan, who last ran for U.S. Senate in 2022, losing the nomination to JD. Vance, is also seeking the Republican nod.

An Emerson College poll, taken in November, showed Brown with a lead on both LaRose and Moreno.

The senator led LaRose, 41-36 percent,  and Moreno, 42-32 percent in the survey.

The endorsement stands to elevate Moreno against his two Republican rivals: Ohio Secretary of State Frank LaRose and state Sen. Matt Dolan, whose family owns the Cleveland Guardians baseball team. In the 2016 and 2020 presidential races, Trump twice won Ohio by wide margins, and he retains a strong following in the state.

As in 2022, when he backed venture capitalist and memoirist JD Vance, Trump’s pick for Senate is a former critic of the man.

Moreno supported Marco Rubio for president in the 2016 Republican primary, and once tweeted that listening to Trump was “like watching a car accident that makes you sick, but you can stop looking.” In 2021, NBC News reported on an email exchange around the time of Trump’s first presidential run in which Moreno referred to Trump as a “lunatic” and a “maniac.”

Trump’s decision to back Moreno is a blow to LaRose, who has taken a number of steps to win his favor. Just days after entering the Senate race this summer, LaRose endorsed Trump for president — reversing an earlier stance that the state’s elections chief should remain politically neutral. The next month, he fired a long-time trusted aide after old tweets surfaced in which the staffer criticized Trump.

Dolan is the one candidate in the GOP field who has not sought to align himself with Trump. Both he and Moreno ran last year for the open Senate seat won by Vance. Though Dolan was a late entrant into the crowded and bitter GOP primary, he managed a third-place finish.

Ohio Democratic Party spokesperson Reeves Oyster reacted to the news of Trump’s endorsement of Moreno.

“Bernie Moreno has made it clear he won’t fight for Ohioans and doesn’t understand the issues facing their daily lives,” she said. “As this primary heats up, it’s clear this slugfest is only going to get messier, nastier, and more expensive from here.”

A poll by Survey USA, taken from Dec. 8-12, before Trump’s endorsement, showed LaRose leading the Republican field, at 33 percent of the vote, with Dolan at 18 percent and Moreno at 12 percent. 35 percent of Republican voters were undecided on the nomination.

The Associated Press contributed to this story.