In Chicago, The Change to Win union federation meets today to vet Democratic presidential candidates, and like so many other union conclaves this year, a joint endorsement is unlikely. That no doubt frustates Ex-Sen. John Edwards's campaign, but they can some solace from the fact that at the SEIU member straw poll in Washington last week, Edwards received the support of some 55% of the members, according to labor and political officials.

Tallies for Sen. Barack Obama and Sen. Hillary Clinton were not available, although SEIU officials have implied that Obama placed second and Clinton placed third.

The New York Times's Steven Greenhouse explains the simple mathematics: though a majority of the SEIU board -- and even the CTW executive committee -- may prefer Sen. Edwards, the membership is sufficiently divided. A bare majority is not enough; a supermajority is needed in order to ratify the preferences of SEIU members.