Hitting a fixed point anywhere on Earth is not that hard anymore.
Hitting something moving is tougher. Not because of the motion, but because of the trouble of finding it in the first place and then keeping track of it long enough to get a weapon to it.
So if we know you’re in bed at 123 Anystreet in Saskatoon, you’re toast. As is your house & your immediate neighbor’s houses.
Now the time of flight of the missile might be a few hours depending on where we launch from; cruise missiles are called that because they cruise; and slower than airliners do.
So if we’re being sneaky and launching from the Gulf of Mexico so the track is mostly over our territory where we can deny seeing anything, we’ll need to launch at bedtime to catch you in the wee hours. So no instant death at the press of the Presidential button.
Now as to denying it sucessfully, the others above have pointed out it leaves wreckage. With “Made in USA” stamped on lots of the parts. “Plausible deniability” would quickly become “epic fail”.
Now where we don’t care that everybody knows we did it, or where that’s really the main point we’re trying to make, things are different …
Over in Afghanistan & previously Iraq, USAF has been working on what they call persistent armed loiter along with persistent total surveillance. It 's still in it’s infancy, but USAF & the defense contractors are a determined and industrious bunch with a lot of brains and even more money …
Imagine a high altitude drone watching an entire county (not country (yet)) looking for Abdul al VeryBadGuy. Nearby is another drone loaded with a few bombs or missiles. Both are far enough up you can’t see them, hear them, and they’re stealthy enough to not be trackable with any practical radar.
Surveillance drone sees a cool-looking armed pickup truck pull out of a garage. Checks the plate & the intel; It thinks, “yep, I bet that’s him”. Asks the humans sitting in a building in Nevada “Can I haz kill it? Please, huh? please!!”. Bored human looks at screen, says “It looks like an armed pickup to me, what the heck, go for it.” Drone says “Cool, dude. kthanxbye.” And calls its pal, the drone with the missiles.
“Hey buddy. Abdul’s northbound on Hwy 3 just past An Whacked village. Do you see him?” “No, lemme turn around … OK there he is. White pickup with red sedan following?” “Yep. Waste Him.” Missile launch to impact time 10-30 seconds. Total time from when surveillance picked up the truck?. We’re working to make it 2 minutes, but 10 is more realistic.
Unfortunately it turns out the pickup was a wedding of Abdul’s neighbors & the attack killed a lot of kids. Or at least that’s what Abdul’s pals put out on the internet. Oops.
Sleep tight, World. Our tax dollars are hard at work making you safer every day®.
The only realy scary thing is the Chinese and Russians are hard at work too. Aways behind yet, but they’re smart, motivated, and even less fun to deal withthan we are. Sucks to be human in the 21st Century. Or at least it will in another 15-30 years.