How was the American Indian population dramatically reduced from the time Columbus discovered the Americas to the 1900's?
Typical "hate America" statements made on this question are best represented by Ward Churchill's book "A Little Matter of Genocide".
In his book, he uses the term "Native American Genocide". Also,
"During the four centuries spanning the time between 1492, when Christopher Columbus first set foot on the 'New World' of a Caribbean beach and 1892, when the U.S. Census Bureau concluded that there were fewer than a quarter-million indigenous people surviving within the country's boundaries, a hemispheric population estimated to have been as great as 125 million was reduced by something over 90 percent. The people had died in their millions of being hacked apart with axes and swords, buried alive and trampled under horses, hunted as game and fed to dogs, shot, beaten, stabbed, scalped for bounty, hanged on meathooks and thrown over the sides of ships at sea, worked to death as slave labourers, intentionally starved and frozen to death during a multitude of forced marches and internments, and, in an unknown number of instances, deliberately infected with epidemic diseases". (Ref: A. Clare Brandabur's Review).
Ward's thesis cites Thomas Brown's work. Thomas Brown discredit’s Ward Churchill’s genocide claim. 2/8/05 – "nearly every element of Churchill’s story is a total invention".
To further weaken the "Genocide" idea, here is what Jared Diamond, in "Guns, Germs, and Steel", a Pulitzer Prize winning book p78 and a National Geographic Documentary movie, says:
"Throughout the Americas, diseases introduced with Europeans spread from tribe to tribe far in advance of the Europeans themselves, killing an estimated 95 percent of the pre-Columbian Native American population. The most populous and highly organized native societies of North America, the Mississippian chiefdoms, disappeared in that way between 1492 and the late 1600's, even before Europeans themselves made their first settlement on the Mississippi River."