Speaker John A. Boehner, R-Ohio, is taking on a new and formidable immigration policy director, a sign that he could be more serious about passing immigration legislation than his critics suggest. Rebecca Tallent, who currently serves as director of immigration policy at the Bipartisan Policy Center, will join Boehner’s staff on Wednesday. Before joining the BPC, Tallent held several senior staff positions with Sen. John McCain, including chief of staff. During her time with McCain, she helped the Arizona Republican draft a handful of immigration overhaul measures, including the last big push McCain made with the late Sen. Edward M....