[img]http://d.yimg.com/a/p/ap/20100728/capt.9190984d339f4e6fad37ef6abb674f08-e87928481e3b46c69b7d132c4ac474cf-0.jpg?x=130&y=100&q=85&sig=4BNTgcJ8WuRMWuiQkU0piw--[/img]AP - A federal judge stepped into the fight over Arizona's immigration law at the last minute Wednesday, blocking the heart of the measure and defusing a confrontation between police and thousands of activists that had been building for months.