Today kicks off the 76th annual meeting of the United States Conference of Mayors in Miami, the biggest gathering of city leaders in the country. Democratic nominee Barack Obama is slated to the crowd over the weekend, as is Bill Clinton.

It's fitting for this urban policy summit to be held in a Southern city. As the Census Bureau reported this spring, the South has the fastest-growing cities in the country:

[E]ight out of the top ten fastest growing metro areas [are] located in the South, and the South also [accounts] for more than half of the 50 fastest growing regions.

These burgeoning urban centers in the South were decisive in Obama's victory in several Democratic primaries.

Another coup for the South: Leaders from Louisville, Kentucky will accept the conference's award for "most livable city" after beating out Las Vegas, Orlando, Seattle and others in the "large city" category.

But not all are happy with the summit's agenda. A coalition called the Right to the City Alliance -- which includes 23 grassroots groups from across the country -- argue the conference isn't dealing with systemic poverty, homelessness and other challenges facing urban America:

Over the last twenty years, the federal government is cutting programs and services, placing a greater burden on state and city governments. Unable to handle the pressure, cities are using neo-liberal policies and privatization to sell land, programs, and resources to make ends meet. As a result, instead of working with community, labor, cultural, academic and faith-based communities, mayors are cutting deals with luxury developers and multi-national corporations.

The coalition will be hosting a Day of Action targeting city leaders this afternoon; check here for further updates.