I can see why the nuclear powers would want to stop LENR. LENR is a prodigious generator of muons. It would be possible to place a satellite into orbit with a LENR source of muons that could be concentrated into a beam and projected onto the ascending warhead in the boost phase. The muon beam would catalyze fusion in the structure of the warhead as well as inside the plutonium pit itself. These muons would produce enough neutrons to prematurely start a chain reaction in the warhead thus exploding the warhead over the territory of the aggressor nation.
Muons cannot be easily shielded at least by anything that can be boosted into space. LENR can produce the ultimate defensive nuclear weapon.