President Obama receives majority support from professional workers and service workers while Mitt Romney gets strong backing from business owners and people in the mining, construction, fishing and farming industries. From Gallup:

Vote Preferences Among Workers, by Job Category, April-May 2012

Not surprisingly, the industry divide mirrors the large city vs country geographic divide in our politics. People employed in industries normally found in more rural places such as mining and farming vote Republican, while those employed in jobs found mostly in urban area such as service workers support Democrats.

The fact that Obama does so poorly with people in the “construction or mining workers” at least partly explains why he has done embarrassingly badly in Democratic primaries the Appalachian coal states. While Obama’s environmental record leaves much to be desired, it is not nearly as extraction industry friendly as the GOP’s “drill here drill now” position.