The overwhelming security effort in the downtown area where the G20 meetings took place reminded me of the Green Zone in Baghdad which is the heavily-protected area where parliament meets and many officials have their offices.
Both areas were shut to normal traffic by police, troops, bomb-sniffing dogs, checkpoints and barricades. Military helicopters, including gunships, frequently buzzed over both zones.
In Pittsburgh, buildings were protected from the threat of rock-throwing protesters by boarding up windows and a setting up a kilometer or so of temporary heavy steel fences more than two meters tall. In Baghdad officials coped with the threat of car bombs by installing many kilometers of concrete blast walls about three meters tall.
In both Baghdad and Pittsburgh security and other activities were watched over by teams of snipers, unseen on rooftops and other places. You only know they are there when the shift changes and the overnight crew heads home to rest, presumably after a different squad goes on duty. In both cities these guys try unsuccessfully to be unobtrusive by putting their weapons in cases.
In both Baghdad and G20 Pittsburgh, getting to a press conference or other activity is an odyssey that takes a frustratingly long time.
The last time I was in Baghdad, about two years ago, getting into the Green Zone required elaborate credentials, and getting through a series of checkpoints. Passes were checked at every step of the way. At other stations in the process, visitors passed through metal detectors, explosive detectors, and were screened by bomb-sniffing dogs and had equipment searched and checked. Parts of the process were repeated when visitors entered official buildings.
In Pittsburgh, officials had visitors place equipment and baggage in a place for bomb-dogs to check. Security officers then methodically searched every item in every bag, and made sure that every piece of electronic equipment actually worked to keep the shell of a laptop or camera from being used to conceal a weapon.
Fortunately for Pittsburgh, the elaborate and obtrusive security apparatus is just a temporary obstacle.
Pittsburgh residents are probably relieved that the uproar over the G20 has ended - and the presidents, prime ministers, the massive security force, the horde of reporters, and the thousands of people who protested various policies and assorted injustices - have all gone home.