I made this point in my brief on California for our Super Tuesday Primer, but Josh Barro explains at greater length why the screwy way the California GOP awards its delegates is likely to screw over Mitt Romney, even if (as looks increasingly possible) he wins the statewide vote:
To fully understand the perversity of this system, realize that some California congressional districts have almost no Republican voters. Diane Watson's (D) 33rd District cast only about 30,000 votes for George W. Bush in 2004; compare that to a strongly Republican district, Wally Herger's (R) 2nd, which gave Bush 169,000 votes. Each Republican in the 33rd District will have nearly six times' stronger a voice in this primary than a 2nd District Republican. ...
Let's say Mitt Romney wins every district with a Republican congressman and John McCain wins every district with a Democratic congressman. Romney will win the statewide vote, because those Republican districts will cast many more primary ballots than the Democratic ones. He'll take home 19 x 3 + 11 = 68 delegates. But John McCain will take 34 x 3 = 102 delegates.
Of course, it’s a big assumption that the wins will break down this way. However, after we classify the state’s congressional districts by likely winner, I reach essentially the same conclusion.
Originally, of course, this system was to benefit Rudy Giuliani, who presumably would have done quite well in a lot of Democrat-heavy districts and badly in Republican districts. But in what's becoming something of a pattern, the rules set up by state Republican parties in socially liberal states to funnel the nomination to Giuliani are just going to end up giving it to McCain.