Seems like Republicans’ letter was a last ditch effort to stall the progress on Iran deals.
Exclusive: Major nations hold talks on ending U.N. sanctions on Iran - officials | Reuters
Major world powers have begun talks about a United Nations Security Council resolution to lift U.N. sanctions on Iran if a nuclear agreement is struck with Tehran, a step that could make it harder for the U.S. Congress to undo a deal, Western officials said.
The talks between Britain, China, France, Russia and the United States — the five permanent members of the Security Council — plus Germany and Iran, are taking place ahead of difficult negotiations that resume next week over constricting Iran’s nuclear ability…