Just by looking at the chart yes every city below the line is obviously democrat run, conversely by looking at the chart, without looking them up, I can only identify MAYBE three cities above the chart that might be republican, but I would think across the board of all major cities in the country, the ones doing the best or at least holding their own are republican run, and lets face it no city is doing anywhere near as well as it should be; the whole country indeed the whole world is suffering tremendously under the obama regime.
Can we assume democrat cities in democrat states are doing the worst?