Being alive is not having the 'right' to live. And being killed is not having the 'right' to live taken away. I was pointing out that this is not a right at all, and that life can be arbitrarily ended for any reason, with no opportunity for recompense.
Actually there are a number of naitons which secure property rights more absolutely than the USA; many are marked by massive rich-poor gaps, rampant poverty, and a fundamental inability of the lower class to pursue life, liberty, or happiness. Therefore it is at best 'unclear' whether increased protection of property rights leads to a higher standard of living and better economic growth.
Arguing about why, exactly, the natives were less technologically advanced than Europeans is pretty hard to do; maybe it had something to do with thousands of years of practice in the science of warfare througout Europe, and before that in Rome, Greece, Mesopotamia... The situation in North America seemed to, for the most part, foster a human population in relative equilibrium with the environment, and not one constantly competing for resources. It's way beyond my trianing to speculate anthropologically why this might have been, and I want to make it clear I'm not calling one group of people better than the other ethically, or anything of the sort. I just think 'property rights' are a poor explanation for what happened.
Life can be ended for any reason, yes, no one is Superman/impervious to death. However, if you say that people don't have an inherent right to life, then what you're actually saying is that everyone else has more right to your life than you.
In what sense do the countries you speak of secure property rights more than the U.S. and what are those countries? I can't respond to your point until I know what specifically we are talking about.
As far as the Natives, yes there may have been other outside reasons for their inferior technological development. However, the reason the 'white man' had guns, and the reason our society is advanced is directly B/C of competition. So while Lack of progress may, for whatever reason, be attributed to something other than competition (which is doubtful but not impossible). Progress on the other hand, in and of itself, is the result of comeptition. It follows then, that without property rights competition cannot exist, since anyone's property by anyone's decree can be yours - which would eliminate competition, and therefore progress.