SPRINGFIELD, Ill. (AP) — Candidates for president have officially filed to get their names on Illinois’ primary ballot. All major Republican and Democratic candidates filed their nominating petitions with the Illinois State Board of Elections by Wednesday’s 5 p.m. deadline. So did three lesser-known, long-shot candidates. The campaigns also filed petitions for delegates to support them at this summer’s national conventions. In Illinois, voters participate in a “presidential preference” poll, in which they cast a largely symbolic vote for the candidate of their choice. Primary voters also elect delegates to the national convention who’ve pledged their support to a particular candidate. That’s the bigger prize for candidates hoping to get their party’s nomination. The March 15 primary field won’t be set until after the Jan. 13 deadline for people to object to candidates’ petitions.