One way or another, it looks like a major congressional battle is headed our way over the U.S. Postal Service’s long-sought goal of ending most six-day mail delivery. One possible flash point is the postal overhaul bill (H.R. 2309) sponsored by Reps. Darrell Issa, R-Calif., and Dennis Ross, R-Fla., which would allow postal officials to begin moving to five-day delivery within six months of the legislation’s being signed into law. The House’s Republican leadership had hoped to bring the Issa measure to the floor this month; earlier this week, the National Association of Letter Carriers said its “most urgent goal is…