Ken Stolle, sheriff of Virginia Beach and a former state senator, has declined to endorse fellow Republican Ken Cuccinelli in part because the candidate for governor declined to support a friend of Stolle’s, Senate Majority Leader Tommy Norment.

Stolle, who served 18 years in the state Senate before he ran for sheriff of the key Hampton Roads community, said he has no plans to endorse Democrat Terry McAuliffe but will instead remain neutral in the race.

Stolle’s non-endorsement may seem an issue mostly of interest to Virginia political insiders, but his reasoning is symbolic of ongoing deep divisions within Virginia’s Republican party.

Stolle, Norment and Cuccinelli all served together in the state Senate prior to Cuccinelli’s 2009 election as attorney general, a time when Cuccinelli was one of the most conservative members of the Senate and at times clashed with Norment and other more moderate Republicans.

Stolle’s concerns emerged on the same day that Will Sessoms, the Republican mayor of Virginia Beach, announced he will endorse McAuliffe Tuesday.

Endorsing a Democrat for the first time in two decades, Sessoms said he believed McAuliffe was better positioned to boost the Hampton Roads economy and support the region’s transportation and education needs.

Sessoms and Stolle are two in a series of Republicans who have either endorsed McAuliffe or pledged to remain neutral in the race.

Cuccinelli spokeswoman Anna Nix responded to Sessoms’s endorsement of McAuliffe and Stolle’s decision not to back Cuccinelli by pointing to the Republican’s just-unveiled Hampton Roads leadership team, highlighting Cuccinelli’s support from several GOP elected officials in the region.

Norment, who has been the state Senate’s top Republican since 2008, is publicly supporting Cuccinelli for governor. But Stolle said he was concerned to hear that Cuccinelli would not agree to support Norment’s continued role as Senate majority leader.

“I think Tommy represents the future of continued good leadership in the Senate,” Stolle said. “That’s always important to me.”

Stolle said he spoke with Cuccinelli, Virginia’s attorney general, about a month ago and told him he had two conditions before he would publicly announce his support.

The first was that Cuccinelli agree to back Norment for Senate leadership. The other was that Cuccinelli agree that the General Assembly should not place restrictions on stem cell research.

Stolle said he has become especially persuaded that the legislature should not restrain scientific research since he was diagnosed with Parkinson’s Disease in 2004.

“I think we ought to leave the science to the medical experts and not the legislative experts,” he said.

Nix did not comment on Stolle’s assertions regarding Norment or stem cell research.

Norment did not immediately return a call for comment. Jeff Ryer, a spokesman for the Senate Republican Caucus, said Norment’s support for Cuccinelli remains strong.

“Sen. Norment is supporting Ken Cuccinelli for governor and doing everything he can to ensure his election and the election of the entire Republican ticket,” Ryer said. “This seems more like an issue between the attorney general and Sheriff Stolle than anything else.”

Cuccinelli’s most prominent Republican defector so far is Lt. Gov. Bill Bolling, who had planned to run for governor until he was pushed aside by Cuccinelli supporters at a convention earlier this year.

So far, Bolling hasn’t endorsed either candidate, though he has been critical of Cuccinelli — and over the weekend he quietly lobbied the political arm of the Northern Virginia Technology Council to overturn a planned endorsement of Cuccinelli.

The business PAC on Monday stuck by its endorsement and announced it was backing Cuccinelli.

Ben Pershing contributed to this report.