Duck Rogers Gamma Ray Bombs

Like some­thing out of an old Looney Toons reel, the U.S. mil­i­tary is “try­ing to build a death ray bomb”,12271,1018361,00.html. Part of the next gen­er­a­tion of bou­tique nuclear weapons the Pen­ta­gon craves, this one kills by send­ing nuclear gam­ma rays. The _Guardian_ arti­cle talks about how devel­op­ment of the new weapon might lead to a new arms race. This is of course quite pos­si­ble: new weapons throw off the bal­ance of pow­er and often cre­ate the per­ceived need for new defences in a con­tin­u­ing cycle.
One won­ders why the U.S. needs to be build­ing ever more sophis­ti­cat­ed weapons of mass destruc­tion. It already has enough nuclear weapons to ensure total destruc­tion of a coun­try and the two recent wars have shown that its mil­i­tary is quite effi­cient at inva­sion. A gam­ma ray weapon wouldn’t help in a sit­u­a­tion like North Korea, where there are more-conventional weapons they could strike back with that would seri­ous­ly hurt U.S. or its allies (even with­out their renewed nuclear weapon pro­gram their short-range mis­siles would dev­as­tate South Korea and Japan).