Durbin is from downstate back when it was more D than it is now; John Shimkus is his successor. (With 100% of precincts reporting, Shimkus was reelected, over a D opponent, 75%-25%, which shows how much the area has shifted). He might still have some residual support in places.
Durbin does still get credit for his downstate roots. A downstater will get a few percent just for not being from Chicago.
Just because Obama did well in suburbs doesn't make them "blue regions." They're clearly swing regions and have been for a very long time... Why is this surprising? The collar counties were very Republican for years, and they've turned into swing regions since the early and mid-2000s. It should shock no one if they vote for Republicans...
Oberweis ran a substantial media campaign in Chicagoland beginning with radio ads aimed at Durbin during the primary. He continued with radio throughout the fall and added TV as well. As Vosem notes, the collar counties are still Pub-leaning and overperformed for Dems with Obama leading the ticket.
