At the very least, to make a Mossad claim plausible, you'd need to have:
(1) a statement by Mossad issued before Stuxnet was released forecasting that Iran would have a weapon by time T_0
(2) a statement by Mossad issued after Stuxnet was released forecasting that Iran would have a weapon by time T_1
(3) T_1 larger than T_0 by at least a year
(4) a statement by Mossad claiming that there were no significant impediments to progress besides Stuxnet
Again, this all assumes that Mossad is not lying. These are the requirements just as a matter of logic. If you don't have all these elements, you can't claim that Mossad's statements prove that Stuxnet was effective at significantly delaying Iran. At best, you have (2), but without (1), (3), and (4), that proves nothing.
Comments
At the very least, to make a Mossad claim plausible, you'd need to have:
(1) a statement by Mossad issued before Stuxnet was released forecasting that Iran would have a weapon by time T_0
(2) a statement by Mossad issued after Stuxnet was released forecasting that Iran would have a weapon by time T_1
(3) T_1 larger than T_0 by at least a year
(4) a statement by Mossad claiming that there were no significant impediments to progress besides Stuxnet
Again, this all assumes that Mossad is not lying. These are the requirements just as a matter of logic. If you don't have all these elements, you can't claim that Mossad's statements prove that Stuxnet was effective at significantly delaying Iran. At best, you have (2), but without (1), (3), and (4), that proves nothing.
To add another source, John Bolton said last August that Israel had 'a week' to attack Iran as the nuclear fuel would be ready to load at that point:
http://www.foxnews.com/politics/2010/08/17/israel-weeks-end-...
That timeframe has now been extended from 'a week' to 2014+ (according to the NYT quoting both Mossad chief and Clinton)
What happen between these two statements to shift the timeframe estimates so dramatically? Stuxnet.
1) According to the Wikileaks cables, Israel's spy agency Mossad's latest claims foreshadowed that Iran would be nuclear armed by 2011.
http://www.presstv.ir/detail/159244.html
2) Iran not able to build nuclear bomb before 2015
http://www.alarabiya.net/articles/2011/01/07/132525.html
3) 2015 > 2011
4) Israel refuses to take credit for stuxnet. So this is impossible.