[Wonder Warthog]

"Early rockets were spin-stabilized. They are not any longer."

I know that, but it is easy enough to go back to spinning, if desired. At what point in the boost cycle it would be best to impart the spin is an engineering problem. I would guess that the easiest would be to put on the "spin" just at the end of the boost phase, when the warhead "goes ballistic".

[chaosagent]

Yes, but note the article refers to hitting the missile DURING the boost phase, not at the end.

And spinning an ICBM during boost is much more difficult now than it was in the early days.

Trying to spin missiles not designed to be spun would cause mucho problems with the new forces now exerted on the vehicle, flame flow thru the nozzles, etc.

It would probably be necessary to redesign the vehicle from scratch.