WASHINGTON -- America has no more than 20 years before the last of the unprotected but critical Civil War battlefields are "preserved or paved over," the president of the Civil War Preservation Trust said Thursday. Revealing a list of the 10 most-endangered battlefields at a news conference with country musician Darryl Worley, trust president O. James Lighthizer called the hallowed acreage "outdoor classrooms" under serious threat of development. Although the trust has had success in preserving more than 18,000 acres of critical battlefields, including parts of Shiloh in Tennessee, Iuka and Corinth in Mississippi and Antietam in Maryland, important tracts...