Chicago Mayor Richard M. DaleyChicago Mayor Richard M. Daley's stunning decision to step down at the end of this term has at least temporarily sucked almost all the oxygen out of Illinois politics and focused just about everyone's attention on an extremely rare open-seat contest.

There hasn't been an open seat race for mayor since 1947, when Ed Kelly stepped aside so the Machine could endorse reformer Martin Kennelly. Richard J. Daley defeated Kennelly in the 1955 primary, and the rest is history. This upcoming open-seat race is just about the rarest Illinois political event most of us have seen in our lifetimes.