Believe me, it isn't being ignored...
but a lot of people are asking some hard questions about the possibility of actually building such weapons. Beyond that, I'm not certain if I can say anything more on the subject. Not trying to be coy or anything, it's just that I work with a lot of classified information and sometimes it's hard to remember what is and isn't classified. I like my job, so I prefer to err on the side of caution.