For most of his 16 years as mayor of Chicago, Richard M. Daley has made a virtue out of thinking big.

He has transformedwhat was an economically blighted Midwestern city into a bustling metropolis by ordering the construction of parks, persuading aerospace group Boeing to relocate to Chicago and taking personal control of the city's ailing school system. In recent weeks, there has been no let-up in his relentless pursuit of the next big idea.