[Lurking Libertarian]

There are two issues with the state action. One, a non-candidate has no standing, at least that is the consensus of the the federal courts,

"Standing" is a federal-court concept. Some states follow it but others don't. So this may or may not be an issue under Illinois law.

and, two, Constitutional questions can only be decided at the federal court level.

State courts decide federal constitutional questions every day. Those decisions may ultimately be subject to review in federal court, but, as an initial matter many federal constitutional questions are heard in state courts.

[iontheball]

“Standing” is a federal-court concept. Some states follow it but others don’t. So this may or may not be an issue under Illinois law.
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It is an issue in the only court system that can decide Constitutional issues.

[iontheball]

State courts decide federal constitutional questions every day. Those decisions may ultimately be subject to review in federal court, but, as an initial matter many federal constitutional questions are heard in state courts.
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I suppose they can do whatever they want, but their decision isn’t worth the paper its written on.