Indeed, the thought of one of these fuckwits being elected president is worrying. As for how to project America's strength: I guess that everybody who wants to know will know by now there isn't all that much strength to project. All it takes to make the American military piss of asap is a few thousand really determined fanatics and some backyard-built IEDs.
Re Iran: I don't think neither America nor anybody else can do anything about them building a bomb. Not as long as the Chinese and the Russians block every UN-Resolution that would really hurt Iran, like effectively banning their oil from being sold.