He came to Notre Dame to give a speech, he was here last year when he was campaigning.
There isn't really anything special about South Bend, besides Notre Dame, but for some reason he likes to come here, I never hear of him visiting Kalamazoo.
I know it's not because of the Hummer plant because the UAW is a bunch of Bush bashing liberals, and I don't think he would feel very welcome there, which is probably why the only govenrment visitors we ever get are Democrats.