If you’ve been to CQ Politics lately, you’ll see that we’ve posted stories about how the 2008 presidential election played out in the 435 congressional districts. I’ve posted my findings on my site, Greg’s List, and my colleagues put together a terrific map that encapsulates those findings in a user-friendly way. Check it out!

You might ask why we didn’t post this information closer to the November 2008 election. The answer: calculating the presidential vote in each congressional district is a very arduous project.

With rare exception, the boards of election in the 50 states release their presidential vote totals by county, but not by congressional district. The presidential vote by district is an important statistic for CQ, given how rigorously we cover Congress and elections. My analysis of the 2008 presidential vote was the third time I undertook this effort.