At a time when the chances of a political settlement between the United States and Iran are diminishing, indications are increasing that the two parties are approaching a turning point that may redraw the balances of the Middle East. Between an American administration seeking to impose its conditions and prove its ability to deter, and an Iranian regime that believes that the decline in strategic files threatens its existence, the ongoing negotiations appear to be besieged by security and military calculations that go far beyond the limits of the nuclear file.