President Barack Obama has defended the impending nuclear deal with Iran by promising Americans that there will be automatic “snap-back” provisions to restore sanctions automatically if Iran cheats on its obligations: “If Iran violates the deal, sanctions can be snapped back into place,” he said in April. On Wednesday, Russian UN Ambassador Vitaly Churkin told Bloomberg News that there would be no such provisions: “There can be no automaticity, none whatsoever,” he said.

The Russian rebuke came in the same week that Secretary of State John Kerry was in Russia to meet directly with Russian President Vladimir Putin himself (after Kerry promised last year to “go to the hilt” to isolate Russia for its invasion of Ukraine). Previously, members of the Obama administration had promised that Russia could be persuaded to agree to snap-backs, or that a new mechanism could be created to avoid a Russian or Chinese veto at the UN Security Council.

The Obama administration’s case for the Iran deal largely rests on the snap-back provision. Without it, the west is giving Iran sanctions relief and the right to enrich uranium with no means to enforce Iranian compliance with its commitment to allow minimal inspections or keep enrichment within limits. Secretary of the Treasury Jack Lew said last week that snap-back provisions would not involve Russia–an odd claim, given that Russia would be one of the parties to the Iran deal.