CHICAGO (AP) Rahm Emanuel swept into the Chicago mayor's office with citywide support and a promise some might say a threat to tackle Chicago's many problems.

The former White House chief of staff has been true to his word. Along the way, he's ticked off enough people to expect a serious challenge when he seeks a second term early next year.

But at a time when that challenger would be emerging, it's still not clear whether there will be one. Critics are searching for a candidate, but face the obstacle of Emmanuel's bulging campaign fund of over $8 million.

The leading contender could be Karen Lewis, the outspoken Chicago Teachers Union president. She is among those angered by cuts in education funding and a 2012 teacher's strike.