As Iowa caucus winner Ted Cruz makes last-minute appeals for votes during Tuesday’s 11-state Republican primary bonanza, his legal team will quietly urge an Illinois judge to kill a lawsuit that claims he's ineligible to be president.

The lawsuit is being heard in a state court system that grants ordinary voters standing to challenge a candidate’s ballot access, a soft target for opponents of the Canada-born Texas senator.

Many recently filed lawsuits question Cruz's eligibility, but thus far have gone nowhere. A handful have been filed in federal court and several more in state court systems. (Sen. Marco Rubio of Florida, whose parents were born in Cuba, also faces a smattering of eligibility lawsuits.)

The Illinois lawsuit, even if unsuccessful, reveals a less-flashy avenue for contesting whether the conservative leader meets the Constitution’s “natural born citizen” requirement for the presidency, as very few people would have standing to file a federal lawsuit, experts say.

“I do think a state court path is the most promising for challengers to Ted Cruz's eligibility at this pre-nomination stage,” says Harvard Law School professor Laurence Tribe. His GOP rivals are “the only plausible federal plaintiffs, but even their status would be a bit tenuous on ripeness grounds," he says.

Tribe, a nationally prominent legal expert who taught Cruz constitutional law, said earlier this year it’s unclear if Cruz meets the Constitution’s undefined “natural born citizen” requirement, giving intellectual heft to Cruz critics.

The Tuesday hearing on the Illinois lawsuit, however, is likely to deal with legal technicalities more so than the substance of the constitutional question.

The man who filed the case, Illinois pharmacist/attorney Lawrence Joyce, failed to properly serve Cruz within five days of the State Board of Election denying his arguments, as state election law requires, argues Cruz’s attorney Sharee Langenstein.

“This lawsuit is nothing more than a misguided attempt to distract voters away from the most qualified candidate for president, Ted Cruz,” Langenstein tells U.S. News. “Given the judge’s knowledge of election law, I feel very confident going into the hearing Tuesday.”

Langenstein, appearing on March 15 primary ballots as a Cruz delegate if the lawsuit flounders, says in her motion to dismiss that Joyce’s email notification to herself and a State Board of Elections lawyer was insufficient, as state law requires service by registered or certified mail directly to the defendants, not their lawyers.

A 2011 appellate state court ruling in Rivera v. The City of Chicago Electoral Board explicitly took ​that position. The broader service issue has been messy, however. Langenstein argued one of several cases to reach the appellate level about who to serve and how.

Joyce argues in his reply to the motion to dismiss that the state’s legal standard for service is confusing and that “this may be the proper time for the Supreme Court of this state to take a case such as this.”

Joyce supports the long-shot Republican candidacy of Dr. Ben Carson, a retired neurosurgeon, and tells U.S. News he plans to tell Cook County Judge Maureen Ward Kirby, a Democrat, that Langenstein and Cruz are so closely intertwined, with her being a potential delegate and having represented him before the election board, that service on her was essentially the same as serving the senator.

It’s unclear whether Langenstein was technically under contract with the Cruz campaign at the time Joyce filed his lawsuit or if that will become legally significant.

Cruz was born in Calgary, Canada, in 1970 to an American mother and a Cuban father who later acquired U.S. citizenship. Through his mother he gained automatic U.S. citizenship, but he also gained automatic Canadian citizenship, which he later renounced. Rep. Alan Grayson, D-Fla., has flirted with filing his own Cruz eligibility lawsuit and told U.S. News in January he believes it’s possible Cruz’s mother lost U.S. citizenship while in Canada, a theory the Cruz campaign says is untrue.

Cruz has lost three of the first four state nominating contests to billionaire Donald Trump, who popularized the eligibility issue and periodically threatens to sue Cruz in federal court. Some conservative activists, meanwhile, say they like Cruz but believe he's ineligible.

Joyce says he feels he’s won, regardless of whether the lawsuit against Cruz prevails.