Pull in all troops from around the world and you're looking at 3 million. However, you must station troops overseas so that eleminates a good portion for quelling the citizens. Subtract those who will refuse to play along with hussein and you're looking at probably half. At most, with perks, he could have a million trained troops. With threats and perks, he could build that back up to large numbers of Mmmmm mmmmm Trayvons. However, the Trayvons won't be easy to manage and they'll turn on each other. It won't be a walk in the park but We the People will win.
I think you also need to figure that a good portion of those the won't go along with it won't just sit and watch.
Of course foreign armor units are now being housed in the US from very arid countries to train in desert environments. Go figure.