On September 6, Adlai E. Stevenson III died at the age of 90. See this lengthy New York Times obituary. He was a former Democratic U.S. Senator, and the Democratic nominee for Governor of Illinois in both 1982 and 1986. In the 1986 race, however, the Lieutenant Governor nominee who emerged from the Democratic primary was a supporter of Lyndon LaRouche. In Illinois, parties have separate primaries for Governor and Lieutenant Governor. But in the general election, they run as a team.
Stevenson resigned from the Democratic ticket rather than run in November in tandem with a LaRouche supporter. That left the Democratic Party with no nominee for Governor and Mark Fairchild for Lieutenant Governor. That ticket of no one plus Fairchild received 6% of the vote. If it had received less than 5%, the Democratic Party would have ceased to be a qualified party in Illinois.
Stevenson then formed a new party, the Illinois Solidarity Party, and ran as its gubernatorial nominee, polling 40.0%. That made the Illinois Solidarity Party the first fully ballot-qualified third party in Illinois since 1924. The legislature, which had a Democratic majority, passed a bill to let a qualified party cease to exist, because after the 1986 election was over Stevenson had no use for the Solidarity Party. But Republican Governor Jim Thompson vetoed the bill, so the Solidarity Party remained ballot-qualified for the 1988 and 1990 elections. Activists from the New Alliance Party captured it, so that it nominated Lenora Fulani for president in 1988.