The facts I'm sure of don't add up.

Flashback: 1942; The Manhattan Project

Starting from just speculative theory in 1942, the United States produced not just one, but two different atomic bombs ("Fat Man" and "Little Boy") by late summer in 1945 - which both worked. Both were dropped on Japan.

Back to the Present:

With full knowledge of how the process works (you can take university courses about it), the Iranians have been working on producing "an atomic bomb" since the 1950's and full steam ahead since 1989 after Ayatollah Khomeini died. (He thought nuclear weapons were evil, so he didn't allow development. Who knew he was on our side? How many religious nuts here might be effectively on the other side due to what they're doing to our own technical progress? Anyway ... I digress.) That's at least twenty years, as opposed to the three years it took us from a standing start.

Can someone explain this to me?