This is definitely Daley pushing his own agenda. Meigs poses no threat to the city in terms of terrorism.
It's interesting to note that the bill proposing the additional funds for the O'Hare expansion was declared dead in the water last month due to republican opposition. I suspect this is the Mayor being spiteful.
I'd hate to be the owner of one of the planes stranded on the field, although it looks like there's nothing too big to use the taxiway to get out.
Peter