LOS ANGELES Immigration protests that brought hundreds of thousands of marchers into the nation's streets this spring promised a potent political legacy a surge of new Hispanic voters. "Today We March, Tomorrow We Vote," they vowed. But an Associated Press review of voter registration figures from Chicago, Denver, Houston, Atlanta and other major urban areas that saw large rallies shows no sign of a historic new voter boom that could sway elections. Even in Los Angeles, where a 500,000-strong protest in March foreshadowed demonstrations across the United States, an increase in new registrations before the June primary was more trickle...