In the early 1960s the US came up with Operation Chrome Dome which was have B-52s armed with nuclear bombs fly continuous routes near the Soviet Union's borders in response to the USSR's growing ICBM threats.

In 1961 in North Carolina, a B-52 crashed carrying 4 Mark 39 nuclear weapons. One of the bombs activated itself and nearly detonated. There was a single safety switch that prevented it from detonating.

A few months later another B-52 crashed in California carrying 2 nuclear weapons. Both safety devices inside the weapons prevented them from detonating.

In 1964 another B-52 crashed in Maryland with 2 nukes, both weapons were recovered.

In 1966 when a B-52 carrying 4 nuclear weapons crashed into a KC-135 while aerial refueling over Palomares, Spain. 2 of the nukes had their conventional explosives payload detonate and blanketed the Spanish countryside with radiation. The contaminated soil had to be shipped back to the US and I think they're still cleaning up the mess to this day.

The worst accident was the last and final mission to Operation Chrome Dome in 1968 when a B-52 with 4 nukes crashed in Greenland. This time all 4 conventional explosives payload detonated spreading radiation around the area. One of the bombs was never recovered.

Yeah, the United States doesn't technically keep any registered groups of irregulars or volunteers for home defense. And no, "every able bodied male 18-47 as per the Dick act" isn't a militia.

Reservists and Guardsman are a part of the professional army.