The debate over whether Canadian-born Ted Cruz is eligible to be president is moving from the campaign trail to the courtroom.

Lawsuits challenging the Texas Republican's eligibility for the ballot have been filed in recent weeks by residents in states including Illinois, New York and Alabama who argue he can't be president because he's not a natural-born citizen. Fellow GOP candidate Donald Trump also has threatened to sue over the issue.

Cruz and some legal experts say he's eligible because his mother was a U.S. citizen when he was born.

Lawrence Joyce, a pharmacist and lawyer from Poplar Grove, Illinois, said Friday he filed suit in Chicago because he wants to avoid what he called a potential "nightmare scenario."

He said he fears if Cruz becomes the GOP nominee, Democrats will get him kicked off the ballot in some states or Cruz will be forced to drop out, and establishment Republicans will replace him with a more moderate candidate, such as Jeb Bush or Chris Christie.

Joyce said he's backing Ben Carson but is acting "strictly on my own."

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Cook County Judge Maureen Ward Kirby set a hearing on a motion to dismiss the suit filed by Cruz's lawyer for March 1 -- the first day Joyce said he'd be able to get off work to return to court. By then, ballots for Illinois' March 15 primary will be printed and early voting underway.

The Indiana Election Commission on Friday also was considering a challenge to whether Cruz may remain on the state's May 3 primary ballot.

Asked about his eligibility during a CNN town hall this week, Cruz said by law he's been a U.S. citizen since the day he was born.

"There will still be some that try to work political mischief on it, but as a legal matter, this is clear and straightforward," Cruz said.

Cruz won a similar ballot challenge in New Hampshire in November.