California is considered a Blue State, but is split politically by region. The North, with the exception of San Francisco, and other coastal areas vote heavily for Republicans, while the South is dominated by the Democrats and Liberals. Keep in mind this is the home of Ronald Reagan who was a very popular Conservative Governor.
Democratic candidates will have to capture the huge Latino vote as well as the strong Liberal vote in California, while still connecting with the moderates. The problem with campaigning in California is it's size. Size can only be conquered with money and name recognition. When you couple that with the other primaries on the same date it is going to make it hard to impossible for "smaller" candidates to be elected as party nominees. This gives Hillary Clinton a huge advantage because she is hands down the number one fund raiser and has the most recognized name. The Clinton's have a strong base in California that will be difficult for any candidate to overcome. Barack

The Republican race for the presidential nomination will be a much more open race than the Democratic race unless several candidates fall out after Florida. Long shot Fred Thompson has already dropped out and that leaves California wide-open. John McCain from neighboring Arizona brings his experience momentum from victories in New Hampshire and South Carolina to the California voters. Mitt Romney has yet to win in a state where he did not have ties (He was born in Michigan and both Nevada and Wyoming have large Mormon populations and were therefore ignored by most candidates), but still has done well across the board and finally, he has the money to compete in California. Giuliani has already made his job tough by skipping the early states and putting everything into Florida. If he wins Florida he could ride that waved into a California victory, but his poor showings in all states, especially neighboring Nevada, shows his campaign is little to no chance to win in California. Mike Huckabee is unlikely to make much