Democratic presidential frontrunner Hillary Clinton is ineligible to appear on Illinois’s primary ballot, a petition filed with state officials on Wednesday claims.

The petition argues that thousands of signatures submitted to get Clinton’s name on the state’s primary ballot are invalid for a litany of reasons. As a result, it claims, Clinton’s signature total is under the 3,000 needed to qualify for a spot on the ballot.

A conservative super PAC explicitly opposed to Clinton’s candidacy is behind the petition, which was filed by Chicago resident Brant Davis with the Illinois State Board of Elections on Wednesday evening, just before the deadline for such challenges.

"Hillary Clinton violated rules that even Rod Blagojevich followed," Dan Backer, who heads Stop Hillary PAC, the group that organized the petition, said in a statement. "The sheer number of defective registrants is a typical bit of Clinton sloppiness and their usual lack of respect for the law."

With the assistance of "teams of volunteers," Backer said Stop Hillary PAC reviewed 500 pages of Clinton ballot access signatures and cross-referenced the information with voter registration files and other public records.

Stop Hillary PAC says it found "more than two thousand signatures falling short of the legal requirement," according to its statement. "Now it is up to Illinois political officials, and ultimately the courts, to uphold the law," Backer said.

According to the petition, the Clinton campaign submitted signatures from people who were not registered voters, provided incorrect or incomplete addresses, wrote illegibly, signed the petitions more than once, or signed petition pages that were not properly notarized.

The Clinton campaign did not immediately respond to a request for comment on the petition.

Democrats expect to have 182 nominating delegates in Illinois, according to the national party, the sixth most of any state.

Relevant state regulations are stringent, making Illinois one of the nation’s most onerous for presidential candidates seeking a spot on the ballot, according to election law expert Richard Winger.

State regulators have also been known to kick state-level candidates off of the ballot in the face of petitions challenging their eligibility.

"Illinois has a reputation for having a strict State Board of Elections that at times removes candidates from the ballot after challenges to their petitions have been filed," according to election information website Ballotpedia.