the americans violated the deal under 0bama. under trump, they tore up the deal. under biden, they continue to implement trump's policies. so if the americans want to talk to the iranians, first, the americans have to go and implement what they agreed to do when they negotiated with the iranians previously. the iranian leader ayatollah khamenei said around the time when the nuclear deal was being negotiated that if the americans implement the nuclear deal in good faith, and the europeans by extension, then we can think about discussing other issues. but the americans and the europeans never did that at all under 0bama. forget trump. but trust cuts both ways, professor marandi. there is a trust problem in the united states precisely because they see what iran has been doing since 2018, in terms of ramping up the uranium enrichment programme, and you've gone far beyond even your previous capability of enriching to 20%. you've now got systems in place which allow you substantial