WASHINGTON - The five candidates vying to unseat Democratic Rep. Sam Farr of California have little in common - except their address and the likelihood that they will lose. The Republican, the Libertarian, the Green, the Peace and Freedom candidate and the write-in independent all work from the same donated office space in a former golf shop as they pursue longshot quests to topple the six-term House member. Their improbable arrangement saves money, but it's also a conscious statement about the near-impossibility of beating a congressional incumbent in California. "This American system of a representative government, it does not exist...