Four Republican Louisiana congressmen have backed a redistricting plan that would preserve two north Louisiana-based congressional districts, despite continued population loss in the area. U.S. Reps. Rodney Alexander, Charles Boustany, Bill Cassidy and John Fleming say the map they prefer considers common economic and cultural heritage and looks at historical representation patterns in the state. The plan, which is offered by the chairman of the state Senate redistricting committee, Sen. Bob Kostelka, would largely rework existing districts and protect the incumbent congressmen.