10 ILCS 5/7-30
Previous to any vote being taken, the primary judges shall severally subscribe and take an oath or affirmation in the following form, to-wit:
"I do solemnly swear (or affirm, as the case may be), that I will support the Constitution of the United States and the Constitution of the State of Illinois, and will faithfully and honestly discharge the duties of primary judge, according to the best of my ability, and that I have resided in this State for 30 days, (and only in the case of a primary judge in counties of less than 500,000 inhabitants, have resided in this precinct for the 30 days next preceding this primary), (and in the case of a registered voter, am entitled to vote at this primary)."
All persons subscribing the oath, and all persons actually serving as primary judges, whether sworn or not, shall be deemed to be and are hereby declared to be officers of the circuit court of their respective counties.
10 ILCS 5/7-30