The massive and massively expensive US nuclear arsenal has long just sat on the shelf, a product of a by-gone age in which Pentagon officials were scrambling to produce bigger and more intimidating weapons of mass destruction while knowing that their actual use was virtually unthinkable.

Modernization is changing all that, as officials say the new focus is on smaller yields, and dramatically more precise weapons that would have relatively limited radioactive consequences and, consequently, have turned the unthinkable, according to former Gen. Cartwright, into the “more thinkable.”

Even as President Obama talks up disarmament on a global scale, his administration has been advancing a scheme that’s expected to cost in excess of a trillion dollars to keep the nuclear arsenal modern, and given America’s perpetual war footing these days, those bombs aren’t just for show.

Insiders have been increasingly critical of the plan, saying the administration is both dramatically overestimating the number of nuclear weapons the US actually needs as a deterrent, and “dial-a-yield” weapons that they say are tailor-made for the US to start thinking about a “limited nuclear war.”