Just days after US President Donald Trump called Iran a "rogue nation", Tehran said it has successfully tested a new ballistic missile. According to Iran, the Khorramshahr missile is capable of carrying multiple warheads. When world powers came together in 2015 to sign a nuclear agreement framework with Iran, it was hailed as a historic achievement. It was the first time Iran had agreed to curb its nuclear programme in exchange for the lifting of some sanctions. But two years later, and with a distinctly different president in the White House, that agreement faces an uncertain future. Trump has threatened to withdraw from that agreement. So, where does this leave the historic nuclear pact?