The Republican challenger to Virginia House Speaker William J. Howell has accused him of quietly seeking a change to absentee-voting policy that she says he has been using to his benefit in the closing weeks of the most-watched primary of the state’s legislative contests this year.

The race pits Howell, a 27-year incumbent and one of the most powerful Republicans in the state, against Susan Stimpson, his onetime protege, in a district that lies 50 miles south of Washington and includes Stafford County and Fredericksburg.

Hoping to capi­tal­ize on the GOP disaffection that helped Dave Brat oust then-U.S. House Majority Leader Eric Cantor from his congressional district last year, Stimpson has tried to paint Howell as a tax-and-spend deal-maker who has lost touch with his district’s conservative base.

Howell, meanwhile, has focused on his connection to the Rappahannock River community and has said repeatedly that his leadership deprived Gov. Terry McAuliffe (D) of his top political priority: expanding Medicaid to 400,000 Virginians.

The campaign has been ugly from the start.

Stimpson, who has lost two of her top campaign staffers in recent weeks and lags far behind in fundraising, has accused Howell of increasing taxes as well as secretly sympathizing with supporters of Medicaid expansion and same-sex marriage.

Howell has denied those allegations and has promoted himself as the conservative wrangler of the House Republican supermajority, whose members span the party’s moderate, tea party and libertarian elements.

In the latest campaign spat, Stimpson said Howell asked — and the state elections board agreed — to streamline the way voters request absentee ballots. She said the change was made without her knowledge, allowing Howell an advantage while she remained in the dark.

“This is called cheating,” she said. “This is taking people’s very basic right to vote and trampling on it. This is the culture in Richmond over which Bill Howell has presided, and it’s exactly why I’m running.”

Howell spokesman Matt Moran dismissed Stimpson’s allegation.

“This is a bizarre accusation,” Moran said. “Her accusations seem to be just getting more bizarre by the day. We were just simply seeking clarification on the law. As we were setting up our absentee ballot system, we were just doing our due diligence on electronic signatures.”

At issue is the way voters request absentee ballots in Virginia.

In response to a request for guidance from Howell’s campaign, the board of elections last week said voters may sign absentee ballot request forms electronically instead of printing out the forms, signing them with an ink pen and e-mailing back a scan or mailing the forms through the post office. The change lets voters skip the step of printing out the forms.

It also makes it easier for campaigns, parties and groups to submit requests on voters’ behalf — as Howell’s campaign does through a portal on his Web site.

Edgardo Cortés, commissioner of the state Department of Elections, said the three-member board of elections made the call at a May 13 public meeting. His staff quickly notified registrars and electoral boards in localities and called the Republican and Democratic parties, he said.

“We don’t have the resources to reach out to every single candidate who’s running. We depend on the parties to get the word out,” he said. “We did it all in open session with the board. How quickly candidates react, that’s up to the individual candidates.”

Stimpson’s complaint is that she was not notified directly — allowing Howell’s campaign to encourage his supporters to take advantage of the streamlined process while she could not. She said she has no problem with the substance of the decision but questioned the board’s authority and timing, and she called the public outreach inadequate, saying it created an unlevel playing field.

John Whitbeck, chairman of the state GOP, said he was surprised enough by the board of elections’ move to contact the party’s lawyers for advice on what to do next. He has made no public endorsement in the Howell-Stimpson race.

“Our [Republican Party of Virginia] general counsel and [Republican National Committee] counsel are communicating and will advise us on the best course of action to take going forward,” he said. Asked whether he would rule out litigation, he declined comment.

Voting-rights groups applauded the change.

“Last week’s decision streamlines the absentee application process,” said Tram Nguyen, co-executive director of New Virginia Majority. “Being able to fill out the application electronically provides an added convenience for voters and could help reduce the submission of incomplete applications, which often result in denials.”

She said that Department of Elections staffers meticulously review all requests for absentee ballots, no matter how they are submitted.

The primary is June 9.