Depends on engagement angles and timing of launch. It is not always required that there be course correction to hit something the size of a city - depending on the velocity at which the projectile hits atmosphere. A simple guidance unit would work and could be built from 60s technology - you can build one even cheaper today - remember, it only has to work once on a one way trip.
There we recent rise during both the mercury and Apollo programs that were dicey. It doesn’t take much to skip an object off.
But this is all ridiculous talk that is done when one is drunk. You can live in your sci Fi novel all you want you will fit in with those who think we are living in a computer simulation