On May 8, President Trump “withdrew” the United States from a deal agreed by his predecessor to prevent Iran from obtaining nuclear weapons. US withdrawal was not foreseen when the agreement was drafted, nor was the possibility that the United States might stand in isolation from its closest international partners. Withdrawal also did not mean that the deal ended.
Some have argued that the European states might be able to save the JCPOA but that it looks unlikely that they will be able to do so. Ultimately, it is for Iran to decide whether to accept the agreement with more limited benefits or to withdraw—a move that could put the US on the path to war.
source: Bulletin of the atomic scientists