This hotfix should eliminate the de-sync issues some players reported while playing between standard and special editions of the game, additionaly it unlocks US campaign from the start so you can play it without completing the North Vietnam campaign first.
WARNING: Saves created during missions will become obsolete, but already completed missions will stay completed. Because of this, please finish the mission in progress before installing this fix.
Hotfix versions
For Steam Special Edition of the game
For Steam Standard Edition