10 ILCS 5/8-1

The nomination of all candidates for members of the General Assembly by all political parties as defined in Section 8-2 of this article shall be made in the manner provided in this article 8 and not otherwise.

The name of no person, nominated by a party required hereunder to make nominations of candidates for members of the General Assembly shall be placed upon the official ballot to be voted at the general election as a candidate unless such person shall have been nominated for such office under the provisions of this article 8.