Americans are scared, admittedly. But do they really want this level of xenophobia and extremism? If Mr. Trump's poll numbers weren't troubling enough, his fellow frontrunners, Sens. Ted Cruz and Marco Rubio, are doing well with chicken-hawk promises, too. Not to be outdone, Ben Carson was talking tough, as well, rattling off Cold War era weapons programs that he intends to pour billions of dollars into so they'll be shiny and new. Yes, that's what America needs right now, renewed investment in its nuclear triad of missiles, long-range bombers and submarines — as soon as Senator Rubio explains to Mr. Trump what a "triad" means.