WASHINGTON - President Barack Obama stepped carefully when talking for the first time about the conservative tea party movement, acknowledging it has legitimate concerns about federal reach and spending, but he contended the core of the loose anti-government network is "on the fringe." The latest political phenomenon, barely a year old, has leaders on both sides of the political spectrum puzzled. Republicans want to co-opt the passion -- and votes -- of tea party disciples to help them oust Democrats from congressional control in the fall midterm elections, without losing other voters in the process. As for Democrats, they have...