The Fix has spilled tens of thousands — maybe even hundreds of thousands (gulp) — of words on the 2012 presidential race. (Heck, we started covering it around the middle of 2009!)

But, in truth, the entire race — at least on the Republican side — can be explained in five charts.

Before we get to the charts, a special thanks to the Post polling team — Jon Cohen, Peyton Craighill and Scott Clement — for their help in pulling this all together and to Ezra “King of Charts and Graphs” Klein for the inspiration.)

1. “Very conservative” voters: In any state where the number of voters identifying themselves as “very conservative” exceeds 34 percent, former Massachusetts governor Mitt Romney doesn’t win. Romney is simply not acceptable to the base of the Republican base and nothing he has said or done — at least not yet — appears to change that reality.

2. Evangelicals: Former Pennsylvania senator Rick Santorum hasn’t won a single major state where evangelical or born again voters comprised less than half the electorate.

3. 100K +: If your family income is $100,000 or more, you are almost certainly a Romney voter. (In Illinois on Tuesday, Romney beat Santorum by 27 points among this group.) In any state where more than three in ten voters have a family income in excess of $100,000, Romney wins. (The lone exception is Georgia where native son Newt Gingrich won despite 38 percent of the electorate fitting into the $100,000 category.)

4. Electability: The one thing that all Republican voters agree on is that the most important trait in the party’s eventual nominee is that he can beat President Obama in November. The more people who cite electability as the key candidate trait in making up their mind, the better Romney does.

5. It’s the economy, stupid: When Romney wins big, it’s because of his strength among voters who say the economy is the most important issue facing the country. Romney’s narrow Ohio win correlated to his beating Santorum by only eight points among economic voters. Romney’s convincing Illinois win, on the other hand, was built on a 21-point edge over Santorum among economy voters.