We don't make much steel anymore, but Pittsburgh still produced enough irony as the G-20 summit unfolded to supply arguments around the kitchen table for months to come.

Lampposts and buses were festooned with signs proclaiming "Pittsburgh welcomes the world." Meanwhile, the Golden Triangle was locked up tighter than the county jail, creating eerily deserted street scenes that looked post-apocalyptic.

"This is a really friendly town," residents told visitors, as phalanxes of city and state police on foot and horseback and National Guard in Humvees patrolled the streets and black helicopters circled overhead.

"Downtown is open for business," Mayor Luke Ravenstahl said, as many shops, restaurants and businesses shut down for fear that street closures and barricades would block access for customers and employees, while others boarded up as a defensive measure.

"We're here for a peaceful protest," marchers said as they gathered to demonstrate opposition to global policies that elevate the rich and powerful while dispossessing everyone else, and most of them were, indeed, nonviolent. Yet some self-proclaimed anarchists rampaged through eastern neighborhoods breaking windows and damaging property with riot police hot on their heels.

"We must do something about climate change!" was a frequent rallying cry for officials and the public alike. This, even as one official motorcade after the next burned enough fossil fuel to melt an iceberg, and police repelled some demonstrators with gas canisters that fouled the air we have taken such pains to clean up since the bad old days.

"This exposure will be great for the Pittsburgh economy," officials told anyone who would listen, and it certainly was good for the hospitality industry. Yet many business owners and workers lamented lost revenue and wages due to summit-related closures.

Maybe these contrasts were unavoidable. Temporary inconvenience, permanent improvement, as the road-construction signs say. This city and its residents were genuinely excited about all the attention that the G-20 would bring, except for the ones who were sure it would be way more trouble than it was worth. It seems you can't bring a large assembly of world leaders anywhere these days without bracing for the worst.

Still, I heard a German reporter on the radio saying he'd covered many similar events around the globe and had never witnessed such a militaristic spectacle or desolate-looking downtown.

"It's like a fortress," he said, sounding both perplexed and disappointed.

When Thursday's un-permitted march turned nasty, those boarded up windows didn't seem like such overkill. As to whether the sheer numbers of police contained the unrest or exacerbated it, that one can be debated ad infinitum. A video on the Post-Gazette Web site was rather disturbing, showing police gassing Pitt students who were simply watching events unfold from an enclosed bridge to their dorm and then blocking them from leaving the toxic area. On the other hand, residents of Bloomfield and Lawrenceville said they were grateful for the officers' protection and professionalism.

What the summit actually accomplished in terms of a joint response to pressing global problems remains to be seen. But Pittsburgh officials worked overtime to spread the word of the city's transformation, and the exposure was all good for the local venues that hosted events -- the Lawrence Convention Center, Phipps Conservatory, Pittsburgh CAPA and the Warhol Museum.

Also getting good play was Greenpeace, which pulled off my personal favorite among publicity stunts, with climbers rappelling over the West End Bridge and unfurling a large sign urging climate control.

They blocked no traffic (although police did when they rushed to the scene), risked nobody's safety but their own (Greenpeace said they were all skilled climbers), and went quietly when arrested. Too bad the sign was facing away from Downtown, when there were still lots of folks there to see it. No matter; it was everywhere on the news and the message got through loud and clear -- unlike the message of the anarchists, who seemed mostly to be expressing their hatred of windows.

Now it's all over but the glass repairs. The world leaders have flown off to wreak havoc elsewhere, and Pittsburghers, with our perennial tendency to see the cup as completely empty, are left to ponder the big question: G-20, good or bad for Pittsburgh? Discuss. And please, no irony. We've had enough of that already.

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