Are the presidential polls skewed?

[nomoon]

I've updated the graph with today's data. The trend is remarkable.

Most of the differences between the polls can be explained by a difference in the weighting of the political parties. All data points fit the trend except for CBS News, whose poll gives Obama a two point leads, though they report equal weighting between Republicans and Democrats.

All of the plotted data points are the published numbers that are rounded off to the nearest whole number. I may try to plot later numbers with the raw data.

This is only speculation, but if the data is unrealistically skewed and these graphs represent the skew accurately, then one might expect that the actual voter results on election day would be close to the intercept where the Apparent Democratic Skew would be zero. This would give Romney a roughly 6 point lead.

I have seen polls that show that Republicans currently have a higher enthusiasm, and thus, one might might expect to have a higher Republican turnout. If this is the case, then actual voter results on election day would to the left of the intercept, so the actual Romney lead could be higher than 6 points.