In the video below, Robert Miller shows how the "Doctrine of Discovery" led to the concept of "Manifest Destiny". Professor Miller is the author Native America, Discovered and Conquered: Thomas Jefferson, Lewis and Clark, and Manifest Destiny which looks at American history through the lens of the Doctrine of Discovery — the "legal" basis Europeans used and Americans still use to claim the land of the indigenous peoples they “discovered.”
Miller illustrates how the American colonies used the Doctrine of Discovery from 1606 forward --beginning with the Founding Fathers. Jefferson used it to claim the Louisiana Territory, to win the Pacific Northwest from European rivals, and to “conquer” Indian nations. Eventually, the Doctrine of Discovery became part of American law -- and is still used today.
Click the graphics to see the book or watch the video.