A poster on TPM made the good analogy: adding popular votes for all primaries and caucuses without adjustment is like adding fractions by blithely summing both numerators and denominators. It just doesn't work.
In the nomination contest, some states have primaries open to all voters; some states only allow those who register as Democrats 60 days in advance; and some only allow those who voted Democratic in the last election. Then the caucus states: some report their counts and some don't. And what about the state that had both primaries and a caucus (TX, WA, NE)? Also, how do you handle the reality that fewer voters attend caucuses? Example: in WA state, 32,000 Dem caucus attendees cast votes, but in the (non-binding) primary 691,000 voted, a ratio of 21.6 to 1 primary to caucus voters. In Nebraska, the ratio was 2.5 to 1. (Yes, some of you think caucuses are unfair. Great -- get involved with the DNC and change the rules, but whinging about that now is pointless.)
How in the world do you reconcile all the different methods of selection? You could add all the primary votes, with an adjustment factor for the number of non-Democratic votes, plus the caucus votes of states that reported times a "participation" factor, plus a historical figure for the caucuses that didn't vote. Gets pretty complicated, eh? And just like now, you'd get a hundred different counts, each depending on the assumptions and prejudices of the compiler.
But guess what? You don't have to construct a complicated formula to tally popular votes! It's already been done -- that's what delegates are for! Delegates are the common denominator used to normalize the vote counts between different states and territories. Read that sentence again. And again.
The delegate system was designed so that states had the latitude to settle upon a candidate using their own method, based on preference or history, and still have the national party be able to agree on a final, unambiguous tally. The delegate allocations establish an "exchange rate" between the different jurisdictions. By that analogy, anyone using popular votes to compare the WA and CA results is asking you to trade Yen and Euros on a 1:1 basis -- don't do it! (Unless you hold the Yen....)
