Susan Stimpson is challenging Virginia House Speaker William J. Howell for the Republican nomination for delegate in a district 50 miles south of Washington that includes Fredericksburg and Stafford County. (Courtesy of Susan Stimpson)

The Republican challenger to Virginia House Speaker William J. Howell on Wednesday sued the state over what she says is a change in absentee-ballot rules that gives the speaker an unfair advantage ahead of next month’s primary.

Susan Stimpson, a former Stafford County supervisor and onetime Howell protege, filed suit in Stafford County Circuit Court against the state Board of Elections.

The lawsuit is part of a bitter Republican primary contest between Howell, a 28-year incumbent, and Stimpson in the Fredericksburg-area district. She has accused Howell of favoring tax-and-spend policies out of line with conservative principles, while he has trumpeted his connection to the district and leadership of the Republican House supermajority.

At issue is a May 13 decision by the Board of Elections to let voters sign absentee-ballot request forms electronically instead of printing out the forms, signing them with a pen and e-mailing back a scanned attachment or mailing the forms through the post office. The all-digital process 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 his Web site.

Stimpson said the board acted beyond its authority and circumvented the legislature to make a sweeping change in the rules at Howell’s request. Howell’s spokesman called the claim ­“ridiculous.”

Stimpson also questioned the timing of the board’s action, which came weeks before the June 9 primary and in the middle of the period when voters can request absentee ballots. She said the public was given inadequate notice of the board’s decision, leaving some campaigns unprepared to adjust their absentee-voter strategies.

“Longtime incumbents like Bill Howell cannot be allowed to use their political power to change the rules to benefit themselves within weeks of the election, after voting has begun,” Stimpson said. “We are a nation of laws, not men. Howell’s actions come from desperation, not strength.”

Edgardo Cortés, commissioner of the state Department of Elections, has said the three-member Board of Elections made the call at a public meeting. His staff quickly notified registrars and electoral boards in localities and called the Republican and Democratic parties but lacked the resources to notify candidates individually, he has said.

Howell’s spokesman, Matt ­Moran, said the lawsuit is between Stimpson and the Board of Elections.

“However, her continued attacks against the speaker are simply false and seem to be getting more ridiculous by the day,” Moran said. “As we’ve said before, our campaign simply asked the Board of Elections to clarify existing Virginia law. We never asked for any policy change. We were simply doing our due diligence to make sure we followed the rules.”

In an e-mail to Republicans on Monday, Del. Gregory D. Habeeb (R-Salem) said the caucus started researching electronic signatures earlier this year and, bolstered by an attorney general opinion from last year, asked the Department of Elections for guidance.

“Throughout this entire process, our goal was to proactively determine how the board would view electronic signatures in order to be prepared for the 2015 cycle,” Habeeb said. “If we did not, then I’m confident that the Democrats would have done so, and we would have been left playing catch-up.”

Last week, Stimpson said she had no problem with the substance of the decision, but after studying the issue further, Stimpson campaign consultant Tim Edson said Wednesday that the move would “open the door to voter fraud.”

Del. Robert G. Marshall (R-Prince William) said in a news release after Stimpson raised the issue last week that the state should stop accepting electronic signatures for absentee ballot requests.

“This significant policy change will increase the chance for voter fraud and will place in doubt the integrity of close elections this year and other elections in the future,” he said.