As the Obama administration ramps up the sanctions pressure on Iran to accept meaningful curbs on its nuclear program, it is following a strategy of coercive diplomacy that has a fundamental design flaw. Consequently, President Obama is in danger of achieving the opposite of his intention: Iran may well decide that rather than negotiate a compromise, its best choice is actually to cross the nuclear weapons threshold, with fateful consequences for all.

Obama’s premise is that only by bringing the Iranian regime to its knees, through sanctions on its central bank and concerted efforts to reduce its oil exports, will it give up on its nuclear-weapons aspirations. The fact that Iran’s supreme leader, Ayatollah Ali Khamenei, has now himself labeled the sanctions “crippling,” and that Iran’s nuclear negotiators announced last week that they were ready to come back to the table, have been taken as evidence that the president’s strategy is working. That judgment is at best premature, at worst wishful thinking.

Iran has not slowed its production of enriched uranium. On the contrary, the regime announced earlier this month it was building an additional enrichment plant with more efficient centrifuges. Nor has it cooperated with International Atomic Energy Agency inspectors, who wrongly assumed that the announcement of a decision to come back to the table would result in a greater Iranian willingness to address their concerns.

Defenders of the current strategy will explain Iran’s continued defiance as a necessary prelude to concessions. More likely, what we are seeing are the reflexive reactions of a regime that believes its back is to the wall. The worst thing the Iranian supreme leader could do in such circumstances is show weakness, especially if he fears that his internal opposition could exploit it to challenge his regime from within.