The story in essence is that Iran appears to have blocked access by IAEA inspectors to an underground facility where it has been enriching uranium. So far as I know, both the U.S. government and the IAEA are refusing to comment on the story. But if true, this represents a point of no return, which Iran has staged deliberately to catch us off guard while everyone is studying its lengthy answer to the EU3+3 offer. In my piece in the current (August 28) print edition of National Review, I described precisely this eventuality as a point of no return, and argued that the United States should invoke preemption if this ever happened.

Update:

Loyola found out more about the AP story. It was, no surprize to anybody, “accurate but critically imprecise,” meaning that the tipping point has not been reached.