The Fairfax County Democratic Committee is suing state and local elections officials over what the committee says is an illegal attempt by Republicans to change rules about elections observers with the aim of reducing votes in Virginia’s biggest Democratic stronghold.

The lawsuit, filed Wednesday in Fairfax County Circuit Court, centers on what Democrats say are new restrictions on party observers inside polling places.

For years, the Democrats say, both parties’ observers — often lawyers — have been able to move freely at polling stations. They couldn’t say anything about how voters should cast their ballots, but they could speak with them about their rights. This year, though, volunteer poll workers are being advised in training that the observers may do nothing more than watch.

Among other things, that means the observers wouldn’t be allowed to advise voters who lack proper identification that they can go home and get it, said Cesar del Aguila, chairman of the Fairfax Democratic Committee. Nor would they be able to intervene when voters are improperly issued provisional ballots, which don’t always end up being counted.

“All we want is to do the same thing we’ve been doing for 10 years: making sure that legitimate votes get counted,” del Aguila said.

Given Virginia’s new voter identification law and its status as a presidential battleground state, the stakes couldn’t be higher for Fairfax Democrats. The blue-leaning county is the commonwealth’s most populous jurisdiction as well as its largest source of potential Democratic votes.

Officials with the Fairfax Democrats said the change in rules for observers isn’t the result of a new law or policy. They said elections officials are interpreting existing law differently — and incorrectly.

The suit mentions the county’s new general registrar, Cameron Quinn, who is a longtime Republican activist. It says Quinn’s “instruction to [poll workers] to prohibit FCDC pollwatchers from talking to voters has no basis in law and violates the First Amendment rights of the FCDC.”

As general registrar, Quinn runs the county’s elections office under the guidance of the three-member Fairfax County Electoral Board. Republicans control the electoral board because the GOP holds the governorship. Quinn, who is named as a defendant, did not return phone calls Thursday. Members of the electoral board, who are also named, either did not return calls or declined to comment. A county spokeswoman said no Fairfax officials could discuss the matter, as is policy when a lawsuit is pending.

For months, Fairfax Democrats have been raising concerns about fairness on Election Day. In addition to Quinn, they’ve questioned the impartiality of Hans von Spakovsky, who is vice chairman of the electoral board and one of the nation’s most prominent advocates of voter ID laws, which generally favor Republicans.

In interviews last month, von Spakovsky and Quinn said concerns over their objectivity are unfounded.

“I park my partisanship at the door when I walk in,” Quinn told The Washington Post. With regard to observers, Quinn said she is following state guidelines.

The Democrats’ lawsuit seeks an injunction that would allow observers to do what they’ve done in previous elections. A hearing is scheduled for Friday.