Yesterday, when the Obama Foundation finally made the obvious official—the presidential library would indeed go on the south side of Chicago, and they'd decide on a site within six to nine months—my colleague David Bernstein and I debated whether they'd choose Jackson or Washington Park, now that it's down to two potential sites near Hyde Park.

My instinct was that it would go in Jackson Park, because people like to build monuments near water, and…that's it. Simple and naive, but monument-building can be simple and naive, which is why lakefront activists are always having to fight off new monuments that could be built anywhere in one of America's most physically vast cities.

David thinks it'll be in Washington Park. Obama got his start doing community building, and he's signaled that he'll continue with that after his presidency—so, he pointed out, Washington Park would be a good place to start building.

And he's got a point. Today I was looking at statistics of life expectancy for the city of Chicago, compiled by VCU's Center on Society and Health. Only two community areas fall below a life expectancy at birth of 70 years: West Garfield Park and Washington Park. Now, 69 years is very, very low: no community district in New York City falls below 74 (Brownsville); no zip code in Atlanta or Las Vegas does either. Of the cities they examined, only census tracts in Richmond, Virginia fell below 69 years.

In the end, I'm coming around to David's bet. The two sites aren't that far apart, but as anyone who's studied Chicago knows, there can be a drastic contrast across that short distance.