LOS ANGELES (Reuters) - A California congressional election featuring the dark-horse candidacy of border-control activist Jim Gilchrist has thrust the issue of illegal immigration to the political forefront. Gilchrist became a lightning rod in the immigration debate by founding the local Minutemen volunteer border patrol and is a long-shot candidate in Tuesday's special election in one of California's most solidly Republican districts. But political analysts say his presence on the ballot forced Republican Party favorite John Campbell and others to take a hard line on immigration -- or risk alienating voters frustrated over the issue. Gilchrist, running as an American...