Sure! I just mean that when you move your mouse in Defcon, I believe the game only reads the movement of the mouse rather than the absolute position of it -- the in-game pointer doesn't care what pixel the pointing device is indicating, just the change in position from where it was before. As a result, pointing devices like tablets and smartboards which rely on indicating a specific position on screen don't work properly -- the game ignores where they're pointing, and only registers how they're moving.
(This is just hearsay, I haven't had a chance to try it on a tablet PC etc. myself)