[JoeMusashi]

Milwaukee benefits from being independent but basically apart of Chicagoland. It maintains it's own identity but has access to O'Hare for international flights, entertainment and retail options not available here, a massive daytrip tourist/visitor base, etc. The DNC Convention is coming to Milwaukee next summer in part because suburban Chicago provides a significant boost in additional hotel rooms that don't exist in Milwaukee.

I'd also like to point out that Chicago benefits from having Milwaukee nearby for some of the same reasons, including access to a good third option airport for travelers in the northern Chicago suburbs.