A Warning From Chicago for Hillary Clinton and the Democrats

The runoff election for mayor of Chicago between incumbent Rahm Emanuel and challenger Jesus "Chuy" Garcia is a reminder of why it is so important for Hillary Clinton to have no serious opponent in the Democratic Primary for president. Ms. Clinton and Mr. Emanuel are not exactly similar candidates, and they are running in different kinds of races. Mr. Emanuel is a divisive incumbent who has had a very controversial first term, while Ms. Clinton currently holds no elective office and was generally seen, particularly within the Democratic Party, as very successful in the last job she held.