As far as I know, only two things:
As Macomb and Oakland Counties go, so goes the state of Michigan in Presidential races.
In the 70s and 80s when Republicans dominated, they won these counties. In the 90s and 00s when Republicans lost, they either lost Macomb or Oakland or both (Oakland always).
Nationally, it seems to be a solid, by small margins Democrat state at the National level, whereas it seems to be a solid, by small margins, Republican state on the local level (exception Governor).
People from Michigan can surely enlighten me here.
The times they are a-changing. Historically Macomb has been known for being a solid Democratic county, and next to it Oakland has been known for being a solid Republican county. The 2004 map shows a flip. Interesting. (for those who don't know where they are, third from bottom row of counties, all the way east. The eastern one is Macomb, west of it is Oakland)
Macomb county has pretty much always been a swing county. Oakland has only recently begun its trend to the left, and Macomb will follow for the same reasons: black migration from the city and social issues.
