McALLEN — Employers have become the nation's whipping boy on the immigration front at the peril of the national economy, and a group of them gathered here Friday agreed they needed to press politically for that to stop. “We need to redouble our efforts. The employers need to be in the game,” Bill Hammond, head of the Texas Association of Business, said of the immigration debate in Washington. “Restaurants are not being built, hotels are not being built, crops are not being planted — all for a lack of workers.” The summit sponsored by Texas Employers for Immigration Reform, or...