The Republican/Democratic index
If you’ve never heard of it, the Cook Partisan Voting Index is a valuable tool to examine how our election system has been modified by the census driven, state created voting districts. In a word, known as gerrymandering.
Gerrymandering is the process that states use to change voting districts so that either the Republicans or Democratic parties have an advantage. In that way, seats are safe for the dominant party, and the voters on the other side have their votes neutralized based on where they live.
If you click on the index link above, you’ll see a sortable list which will show you which states are dominant in Republican or Democratic congressional seats. It may not reflect public sentiment, but the legislatures have modified the system to suit whichever side was in power when the districts changed based on census information.
The + and number means the degree of voting bias in those districts. The bigger the number, the more likely that a candidate from the prevailing party will always win.
These are states where Democrats and Republicans are dominant. Note that for reasons you may guess, some of the Governors’ are from opposing parties.