Preservationists are drawing lines of defense around more of America's hallowed ground.

U.S. senators hoping to control development near Civil War sites have introduced legislation to protect two parcels at Gettysburg and preserve thousands of acres of battlefields at Vicksburg, Miss., and Petersburg, Va.

"That kind of historic land can never be replaced," said Michael Kraus, curator of Soldiers & Sailors Memorial Hall & Museum in Oakland and a member of the National Civil War Museum Advisory Council. "These are places where people fought and gave their lives."

Preservation groups recently fought off a developer's proposal to build a casino a half-mile from Gettysburg National Military Park, drawing attention to the preservation issue.

A planned Gettysburg expansion would add 46 acres, including two parcels known as Plum Run and the Gettysburg Train Station. Supporters hope that will happen before next summer's 150th anniversary of the Battle of Gettysburg....