COLUMBUS, Ohio (AP) — Dozens of Republican leaders in Ohio are mounting a last-minute effort to urge former President Donald Trump not to endorse JD Vance in the crowded upcoming primary for an open Senate seat.

A draft letter circulating among Republicans and obtained by The Associated Press calls on Trump to remain neutral in the race. It was written following a news report that Trump was going to endorse Vance, a step the former president has not yet taken.

But the letter is a sign of anxiety among some Republicans about which candidate Trump may pick in advance of the state’s May 3 primary. Vance has come under particular scrutiny from some of Trump’s most loyal supporters for criticizing the former president in the past, something the Republicans highlighted in their letter.

In bullet points, they remind Trump of Vance’s past comments, including references to potentially supporting Hillary Clinton and comparing the former president to “another opioid.”

“We know there are many qualified candidates in this race who have stood up for the America First agenda over the years and have carried the Trump mantle over the years, again with the notable exception of JD Vance,” they wrote. “While we were working hard in Ohio to support you and Make America Great Again, JD Vance was actively working against your candidacy.”

The letter, signed by GOP party leaders, including a slew of county chairs, tells the former president that “an endorsement that cuts against your support and legacy in Ohio will only serve to confuse or upset voters” and may even suppress Republican turnout in the fall.

Representatives for Vance, who has said he regrets his past comments, did not return an email seeking comment. Trump representatives declined to comment.

David Johnson, chairman of the Columbiana County Republican Party, who helped to draft and circulate the letter, said the effort came together in a series of phone calls between party chairs Thursday.

Johnson, who has endorsed former Ohio Republican Party chair Jane Timken for Senate, said the letter has now been signed by between 40 and 50 people, including supporters of Timken, former Ohio Treasurer Josh Mandel, Cleveland investment banker Mike Gibbons and state Sen. Matt Dolan. Two other candidates round out a seven-way primary to replace Republican U.S. Sen. Rob Portman.

“All of us think it’s just not a smart thing to do for winning that seat. That’s the objective,” he said.

Vance supporters, meanwhile, urged Trump to stick with him.

“President Trump would be making a fantastic choice by endorsing JD Vance,” said Marshall Pitchford, the chairman of Ohio Right to Life. “JD is 100% pro-life without exceptions. He will continue President Trump’s pro-life victories in the US Senate.”