Yes, as a matter of course. But the nuclear deterrent was designed for defense against other major powers. Terrorists are stateless, at least nominally so, and to what exact degree do we have to prove that the weapon wasn't stolen? Or misplaced? (The Russians have "lost" countless weapons) Do we hold a nation responsible and vaporize it if some rouge political group stages a coup and supplies a terror group with a weapon? If the coup is then defeated and the old government is reasserted, can that nation prove that the coup was real, and not a merely a firewall against legitimate reprisal? What margin of error is acceptable for being
absolutely certain of the origin of the weapon?
Etc etc etc...
I mean...how well can we possibly know what exact radioactive toys the North Koreans have managed to stash?
Is the message, "You have nukes now, and if one of them gets used, regardless of how it happened, and we can absolutely track it to you...you die no matter what." ? Are there extenuating circumstances, or does Country X get erased regardless? Do we accept tens of millions of civilian casualties, inflicted after the attack, totally as a matter of revenge? I mean, the damage is already done. What if it takes a couple months to track the weapon to Country X? Do we then methodically slaughter that population with an arrangement of plutonium and rocket fuel such that future archaeologists will suspect an asteroid strike? Because, "Well, your government decided to do a bad thing, and so now you all have to die. Don't hate the player, hate the game."?
F*ck this whole train of thought, actually.