G.H. Merritt, a Lake County woman who founded New Illinois, the group hosting the Mount Vernon event, starts her presentation after the prayer and Pledge of Allegiance. She points out to the crowd — now using New Illinois brochures to fan themselves as the overwhelmed air conditioning loses its grip — that the idea of a state split isn’t new. In fact, groups from either downstate or Chicago have tried to secede from Illinois several times since 1840, when a group of northern counties asked to be given to Wisconsin. (The state line was set above the tip of Lake Michigan in 1818.) In the 1970s, a group of western counties dubbed themselves the Republic of Forgottonia. And in 1981, a Chicago legislator pushed a secession bill through the state Senate, as a public poke at downstate counties for complaining about CTA funding. The bill was tabled by then Speaker of the House George Ryan. Most recently, downstate legislators proposed a split in 2011, after election data showed that in 2010 Gov. Pat Quinn won only three downstate counties — and gained the governorship by carrying Cook County.