After the horrors of the Civil War, how did the progress of Manifest Destiny move the American frontier

After the horrors of the Civil War, how did the progress of Manifest Destiny move the American frontier

After the horrors of the Civil War, how did the progress of Manifest Destiny move the American frontier? What were the major changes in economic and territorial expansion that shaped American domestic and foreign policy? How did Theodore Roosevelt push for reform in America and expansion of American power overseas before and during his Presidency? Did Roosevelt’s policies help or hurt Americans in the long run?