California really does have a licensing loophole specifically for Soju though. It originated from some lobbying by folks with restaurant interests in the large local Korean community but other non-Korean restaurants have been taking advantage to make cocktails as well.
Soju Goes Where Vodka Cannot Tread
You can get a mojito, a cosmo and even assorted martinis at Vine, a new fondue restaurant and nightspot in Hollywood.
http://www.leginfo.ca.gov/pub/97-98/bill/sen/sb_1701-1750/sb_1710_bill_19980721_chaptered.html