It's safe to say that 19th century white American and Australian authorities didn't exactly have the well-being of their countries' original inhabitants high on their priority list; in fact, the sentiment that they were dying peoples doomed to extinction and/or that they needed to go extinct was quite common. So, what if, in the 19th or the 20th century, the government of Australia, that of the United States, or both, had been able to exterminate 100% of their respective native populations, not through accidental means, but on purpose, plainly stated on official papers? What would be the impact of such policies on the history of either country, and the world?