Many of these voters eventually changed their party registration and became Republicans, especially in the South.
Election officials say changes are surprising because California recently went to an open primary system, making party registration less important.
Some is definitely in there, including address, phone number and party registration where available.
San Jose now has a Democratic majority in party registration.
Under Measure 65, voters would have received the same ballot regardless of their own party registration.
Washington has no party registration and voters may choose on primary day to vote in either contest.
"And I asked whether we wanted to get into a numbers game given the difference in party registrations."
No party registration is required in the three launch-pad states.
However, he was criticized for changing his party registration.
But Missouri does not have party registration, so it is hard to predict who will turn out for which primary.