A Nation can’t do anything - it’s individuals that God looks at - when you get to a Nation, you are just using statistics to represent what polling and observation tell you is a ‘most likely’ indication.
Many years ago I might have agreed with you, I've kind of changed my mind though. I have a tendency to believe that God doesn't bless and/or curse individuals per say for keeping his commands put blesses and curses groups of individuals for keeping his commands. I have several reasons for this thinking but the main reason is when God speaks to his people in the Old Testament through people like Moses he might say stuff like "...You People..." or just "...you..." In the case of just "...you..." he means it as a plural though as in you people that has been shorten to you. At first glance it may appear God is instructing individuals in his commands and he does that some times but more often he instructs his people. My gut feeling is the blessing and cursing he talks of in keeping the commands seem to be focus in his people and or a group of individuals, So having said that I don't really believe God focuses on ditching out blessing and curses to individuals as much as he does groups of individuals. It is kind of hard to explain, but if I am correct not only do we as individuals have to be concerned about keeping the law, we also have to be concerned about whether our neighbors, our small communities, our churches we goto, are keeping the law. One could extend this thinking beyond ones small communities in which we live to the cities, the States, and Countries we live in but that might be taking it a little bit to far but feel free to take it that far if you please. If we are blessed and/or cursed it might not be so much what we do or don't do in regards to our blessings and cursing but what our fellow men we know are doing or not doing. It is hard to explain but hopefully I've given you a sense of how blessing and curses go as I see it, I may be wrong about how I see it though but at least I hope you and the rest of the freepers that might read this might consider this idea.