A political puzzle...

Following a hunch, I pulled together historical data on US political participation. Here's the result:


The turnout data is from data is from wikipedia. Non-presidential election years are averages for the previous and following election. Polarization data comes from the difference between House party medians in the first two DW-NOMINATE dimensions. Basically, polarization measures how much Representatives' votes broke along party lines.

Here's the puzzle: up until around 1900, the two lines track quite closely. The raw values are about the same, and they tend to move up and down together. But after 1920, the polarization and participation stop tracking each other. Why?

Tracking campaign contributions

Here's a site trying to make campaign contributions more transparent:

http://www.maplight.org/map/us

"MAPLight.org, a groundbreaking public database, illuminates the connection between campaign donations and legislative votes in unprecedented ways. Elected officials collect large sums of money to run their campaigns, and they often pay back campaign contributors with special access and favorable laws. This common practice is contrary to the public interest, yet legal. MAPLight.org makes money/vote connections transparent, to help citizens hold their legislators accountable."

I haven't dug into the site in much detail, but it looks interesting.  Anybody know more?