And keep in mind...
The same NIE that is now being treated by the Left like tablets from Sinai also declared that Iran had an active nuclear weapons program until 2003. A nuclear weapons program that long preceded Bush, operating in various forms since the late 1980s.
There was no serious diplomatic "international pressure" of any kind being applied to Iran in 2003. The current diplomatic efforts, firmer by far than anything that was happening in 2003 (not saying much), are sneered at by Iran.
If the Iranians did drop the program in 2003, it was for one of two reasons: Fear of being dealt with like Saddam was, or realization that with Saddam gone, they no longer needed to deter Iraq.