Advocates for immigrants have gained ground in the last six months in their long fight against a U.S. policy allowing federal immigration officials to screen suspects in local jails. Now they are close to notching their biggest victory yet. In California, the home of nearly 2.5 million unauthorized immigrants, lawmakers this month once again passed the so-called Trust Act, which would block local police from holding suspects for immigration agents when they would otherwise be free to go. Gov. Jerry Brown, a Democrat, has until mid-October to decide whether to sign the law.