A parallel can be drawn between how Iran has been handling their nuke program and how N. Korea did theirs. The N. Koreans got more and direct help setting theirs up from the Soviet Union where Iran has been largely doing it on their own with only some indirect help from countries like N. Korea, Russia (the Soviet Union), and China.
When the N. Koreans started their program, and it became obvious they were working towards a nuke, the US (Clinton as President) tried the bribe a tyrant approach to stopping them. That resulted in their taking the monetary bribes and camouflaging their program far better while making a few overt moves to show apparent compliance. From there, they continued to move towards a nuke steadily, if more slowly, as they had to keep their program hidden. All the while, they promised, vowed, and proclaimed, they weren't trying to make a nuclear bomb.
Once they had either a weapon imminently available or actually had one, they withdrew from the NPT, tested a bomb, and announced they were a nuclear power. More bribes to tyrants followed with more promises by N. Korea to shut down their program. More bomb tests followed, and N. Korea showed they had a number of nuclear weapons available for use.
That was followed by more bribes to tyrants and more empty promises from N. Korea, and that's where we are today. At least N. Korea is smart enough to see nukes as a deterrent that allows the Kim Jong dynasty to rule over N. Korea in perpetuity.
Iran is following the same pattern likely to the same result. Blowing the living fuck out of their nuclear program may not stop them from getting a nuke but it definitely will slow them down. Bribes to tyrants doesn't work, and anything the tyrant(s) tell you is nothing but a goddamned lie. I'm also not so sure that the ayatollahs are only intent on consolidating their power. Religious fanatics, like them, often want to convert everyone else or die trying, meaning they might well use nukes if they have them.