Michael Totten has an excellent post from a week ago that I just got around to reading. He describes the supporters of Bernie Sanders as the alt-Left, holding many views in common with the alt-Right. One of the topics highlighted from Totten's conversations with the Sanders supporters was their attitude towards America's military strength, in which "at least two Sanders delegates said that the United States should completely disarm and have no military at all."
The best response to calls to dismantle our military comes from Scott Adams in the 1980s. There are a lot of unsavory players on the international arena who bully their way through international affairs if a butter knife were adequate to impose their will and that dismantling the US military would mean that those unsavory players would need just a butter knife.