Reagan made that statement about a treaty with Russia, it was with Gorbachev, but Putin has proven to be even less trustworthy. Remember, he's the one who told leaders of the world that he wasn't going to attack the Ukraine right up to the day he did. He's just tested a new ICBM that he believes is unstoppable and can hit multiple targets simultaneously. I don't know that this wasn't allowed with the agreements he made with Trump, no one does who wasn't in the room.
Gary