The velocity of bad sign-spotting is increasing as we get closer to the main negotiations over Iran's nuclear program.

Bad Sign No. 1: I think it's important to note that Iranian President Hassan Rouhani has just stated that under no circumstances would Iran agree to destroy any of its centrifuges. I would also like to note that this unequivocal statement, if sincere, means that there is no possibility of a nuclear deal between Iran and the six powers set to resume negotiating with it next month.

In order to keep Iran perpetually 6 to 12 months away from developing a nuclear weapon — an unacceptable period in the mind of Israeli Prime Minister Benjamin Netanyahu, but a time-frame that U.S. President Barack Obama could conceivably accept — Iran would have to agree to dismantle 15,000 centrifuges; close an important uranium enrichment site; and accept 20 years of nuclear inspections, according to the Institute for Science and International Security, a well-respected (and centrist) think tank headed by the former United Nations weapons inspector David Albright.