California only gave a little over 32% of the vote to Lincoln in the 1860 election, and there was a large pro-Southern sentiment. Albert Sidney Johnston, later a Confederate general, was the commander of US forces in California during the secession crisis, but he remained adamantly against pro-Confederate takeover of US military posts while he was in command.
What if Johnston had joined the secessionists, or, at best, stepped aside and let it happen? There was a move to form a Pacific Republic with Oregon. Could they have convinced Nevada and Washington Territories to join them? What if a viable Pacific Republic was formed in 1861? Was the gold sent east by California important enough to the Union efforts that losing it might effect the outcome of the war?