A Democratic presidential candidate and two Republicans will stay on the Illinois ballot.
The State Board of Elections dismissed an objection to the candidacy of Democrat Hillary Clinton.
The board ruled Republican U.S. Senators Marco Rubio and Ted Cruz can also stay on the ballot.
Two Illinois residents raised questions about the legality of Cruz and Rubio running for president.
One of the objectors is William Graham of Glen Ellyn. He says the senators are U.S. citizens, but they are not natural-born citizens under the law.
"I actually like Marco Rubio,” Graham said, "and I agree with many of his policies. I can't vote for him because he's an illegal candidate. But this isn't about Marco Rubio at all. This is about the Constitution.”
Rubio was born in Miami to Cuban immigrants. Ted Cruz was born in Canada to a U.S. citizen.
The objectors have about a week to file an appeal in circuit court.