Sentence:  The possibility , as he asserted , that the Russians may get ahead of us or <WSD>come</WSD> closer to us because of their tests does not supply the needed ethical premise - unless , of course , we have unwittingly become so brutalized that nuclear superiority is now taken as a moral demand . 
Meaning of the word marked with <WSD> tags:  move toward, travel toward something or somebody or approach something or somebody