@amletusvirgilianus,
The United States is not responsible for the revolution in Syria. Russia is at least as culpable by virtue of their meddling as is the United States. There is no doubt about American involvement in Iraq, which, fortunately, Mr. Obama ended. Bush's nasty little war there was badly mismanaged and certainly did cost the lives of tens of thousands of civilians, but not millions. In Vietnam, it is difficult to separate civilian deaths from military deaths, and to place blame for those deaths. In total, the high end estimate for all deaths, civilian and military is about two and a half million. Assigning blame for these tragedies is problematic, and that is because people are eager to blame someone, and eager for a simple explanation for what are actually complex events.
Perhaps millions of aboriginal Americans died because of European colonization, but certainly not as a result of direct, intentional butchery. Disease was very likely the cause of most deaths. Additionally, it is another complex set of events in which only the simple-minded, or fanatics, will assign blame. When Cortéx invaded what we mow call Mexico, it was absurd to assume that he could have conquered that highly developed civilization with the somewhat more than 400 men he took inland. After the march to Tenochtitlan, during which Cortés picked up thousands of aboriginal allies, he was able to add, perhaps, one thousand more Spaniards. It was the thousands of aboriginal allies who made the conquest of the city possible, and even then, it took almost two years. (For a short summary see
Historia verdadera de la conquista de la Nueva España,
The True History of the Conquest of New Spain by Bernal Diaz, the only eye-witness account. For a more thorough treatment, including accounts by aboriginal people, see
The History of the Conquest of Mexico, in three volumes, William Prescott, Boston, 1843. Yes, I've read both, in English, of course.)
After the cordial reception of the handful of French who arrived in what is now Canada under the leadership of Champlain, the Ottawa solicited his aid against their traditional enemies, the Iroquois. The Iroquois plundered the lands of the Algonquian peoples almost every year, and when their war party was routed by the Frenchmen with their firearms, they were incensed. They began a 150 year campaign to extirpate the French. That included two invasions of Canada, the second lasting for almost two years. Unable to root out what was really an absurdly small French colony, the Iroquois decided to attack them economically--they decided to exterminate the tribes of the Great Lakes region, and thereby cut off the supply of furs and beaver pelts to the French. That went on for generations. As late as the 1680s, the Iroquois invaded the territory of and attempted to exterminate the Illiniwek, the people the French called the Illinois. They killed far more aboriginal people than the French and the English combined. (For the madness of those times in Canada, see
France and England in North America, in seven volumes, 1865-92, Boston, Francis Parkman. Parkman was a bigot with no respect for the aboriginal peoples--but his scholarship was beyond reproach.
As with any such work, it needs to be reviewed wth several grains of salt.)
The tale of European colonization in Africa is one of even greater slaughter and horror. Assigning blame is idiotic, and always a product of the prejudices of the one who attempts to do so.