Eisenhower should take some credit for moving the strategic reserve - the US 101 and 82 Divisions 'fresh' from Market Garden - to Bastogne and St Vith respectively, early in the battle.
But without the 7th Armoured at St Vith and elements of the 9 and 10 Armoured divisions at Bastogne, they probably could not have held the Germans up.
Particularly at Bastogne, the defence put up by the other units, rather than the gallant 101st, seems relatively rarely acknowledged in popular culture.