There are a variety of people who still earn a lot of money and/or air time basically proposing that the US can simply wish something in foreign policy and it will happen, through dint of Moral Authority and Economic Dominance and (of course) Military Might. It's amusing, given our current (and ongoing for decades) relative impotence regarding North Korea, that these same folks — neocons, and fellow travelers — make the same noises about Iran.
"We should just bomb them!" Because that's an awesome thing to do. "We should embargo them harder." Uh, we did, and it really didn't make a difference. "We should promote regime change!" Yes, because imposing (or actively supporting) regime change in Iran always works out well for us.
If there were simple answers that would work — well, then even simple presidents could come up with them.
Two Years on, the Iran Deal is Working
It is true that Iran’s behavior in the region has not improved. But it is also true that this behavior cannot be attributed to the nuclear deal.