The venerable Field Poll, a California-based polling firm, gives Obama a 22 percent margin in California among likely voters.  Both campaigns bypassed California, except to raise money, but 22 points, if it holds, would be significant. 

But, the election is not determined by popular vote, as President Gore learned in 2000, it is determined by the Electoral College, a state-by-state count of a state's representation in Congress equaling a state's two senators plus the U.S. Representatives. 

This opens a very interesting question.  Since California accounts for 1 of every 8 voters, and since many national polls have Obama ahead by 3 points, what would the result for the national polls be if California was excluded?  Dead even.  Obama's up 30 points in New York, so, exclude New York from the picture and McCain would win the remaining 48 states by 1.5 percent. 

The Electoral College was put into place by our Founders to prevent a presidential candidate who was wildly popular in a single region from winning without the support of a good portion of the rest of the nation.  They wisely reasoned that a President, to be President of the entire nation, should ideally win majority support in a substantial number of states.
 
Election Day and night may be a long one.  Pay attention to the margins in Pennsylvania, New Hampshire, Florida and Ohio.  If McCain does well there, it won't matter how much support Obama racks up in New York, Illinois, and California.