Smith was wrote the Wealth of Nations as a criticism of Mercantilism...his economic experience consisted of a brief stint as a customs official. He wrote Moral Sentiments much earlier (1752 I believe) and I believe it to be a moral blueprint to support his system of economics. As for Harrington's perspective on Hobbes, here's another view on the formation of the state and obligation of citizens. http://www.jstor.org/stable/2938736
Olson is a remarkable guy, I saw him present this at the APSA conference in '93 when I was there presenting a paper on NAFTA...I think you'll enjoy his perspective.