Well it is in effect America's fault for regime change in Iran in the mid 50's and installing our puppet the Shah of Iran who was brutal and the Iranians have never forgiven us for inflicting that upon them. So when they rightfully revolted we froze their money. It was their money.
We have their military bases under 7x24 surveillance by satellite and they have reduced their centrifuges where they couldn't enrich enough plutonium and we have under 7x24 video where they store uranium and mine their yellowcake. What do we have now? So tell me oh smart one who makes centrifuges and how does one obtain them? Oh and what other material might Iran need to manufacture a bomb that is not tightly controlled. We have surveillance on what intelligent people who know what they are looking for need to know.