This entire article smacks of determinism. To argue that issues at the founding of the United States, and the cultures involved therein have any bearing at all on today's policies requires some sort of mechanism whereby such issues are perpetuated to today. The closest that Rosen comes to that is "Child rearing" techniques of the Scotch-Irish and the Protestants. However, I am pretty sure that outside of a few groups which may still be around, those techniques died out decades if not centuries ago. Sans such techniques, the only explanation for why todays Scots Irish or people of "Puritan" extraction would in any way resemble those of past descent is some sort of genetic/cultural determinism.

The question then remains, insofar as Scots Irish and Puritans are not unique to the US(Canada, Great Britain, Australia?), why then is such a culture unique to the US. Of course, the answer is, that the US is not particularly bellicose, and our wars are almost always less popular at the time that they are being fought than they are remembered. One example given by Rosen is the Mexican American war, which was actually tremendously unpopular, and opposed broadly by the opposition Republicans, led in part by Abraham Lincoln. I remember reading in Gallup polls that support for WWII in Dec 1941 was about 60%, after Pearl Harbor!

It is interesting that Rosen would bring up John Mearsheimer in support of his argument, insofar as anyone who has read The Tragedy of Great Power Politics could tell you that according to Mearsheimer, culture has nothing to do with bellicosity, one way or the other. As a structural realist, Mearsheimer argues that structure is what creates bellicosity. Therefore, the real tragedy is not that the U.S. cannot be content with its safety behind borders, but that because of the security dilemma no Great Power can ever be content to simply rest within its borders. The reason that Europe was bellicose in the past, and is now not so, is not that they have received some cultural enlightenment but because they are no longer great powers.

In the end, Rosen seems like he is trying to argue against the theory of Democratic Peace, but he picks only one explanation of it. I am simpathetic to his intuition. Nevertheless, he has no mechanism, nor justification past genetics to believe that even if the premises which he sets forward as occuring at the founding are true continue to today. Moreover, he never shows, and I think that there is a great deal of question whether there is reason to believe that the U.S. is more bellicose at all. Attacking only the cultural explanation of the democratic peace with another cultural explanation boils down to claiming that there is no such thing as the democratic peace. Unfortunately, that argument has been had over and over again, in much better publications, and ceased to be interesting a long time ago.