Like most other governments around the globe, the U.S. government has expressed deep concern about Iran's nuclear plans. There are good reasons for this, although Iran is probably several years from making a nuclear bomb.
But is this the only motive for the U.S. government to put Iran on the agenda?
As we all know, the present U.S. administration has no credibility, so other - unspoken - motives might very well be much more important.
As far as I can see, the question of "Petro-Dollars versus Petro-Euros" is a good candidate, and you can find an interesting article about this on my blog Essays & Articles.