Michael Barone in The Washington Examiner: If Republicans run as strongly as Brown, only 103 House Dems are safe.
Let’s extrapolate those numbers to the nation as a whole and assume that a district that voted 64% or more for Obama is safe for Democrats even under the most dire of circumstances. How many such districts are there? Answer, according to this source: 103. The other 332 districts voted 63% or less for Obama. Interestingly, there are more 64%+ Obama districts in the West (36) than in the East (27) and more in the South (21) than in the Midwest (19).
