Gerrymandering by latino and black caucus

http://www.npr.org/2011/10/31/141457122/chicago-leaders-spar-over-redistricting

Lobbyists that want to redraw voting district lines so that minorities get more representation....

The city's Latino population is now at nearly 30 percent. Alderman Danny Solis, who heads the City Council's Latino Caucus, says the ward map the Black Caucus proposed is simply a starting point. It would drop one majority black ward and create two more majority Latino wards.

"The numbers we have now are not enough. The figure speaks for themselves. We are in need of more Hispanic wards in the city of Chicago," Solis says.

>>11

I'm not >>10, but if blacks are moving out and latinos are moving in at the rate this article says, then why are the districts not becoming latino majority naturally by replacement?  Why are the lines having to be redrawn.  It seems to me that in voting numbers are supposed to be what matters, I don't understand Solis' statement, "The numbers we have now are not enough."  It sounds to me like he does want special privileges.