Theres a few rules that relate to this, basically:
a) must be within 5 hexes at the moment of combat to be allocated Support Units from the HQ (artillery etc);
b) Leader effectiveness starts to decline with range and HQ hierachy.
In this case a corps commander gives out their full leadership scores if within 5 hexes, army commanders work at 15 and so on. Morale ratings have no distance modifier (which is often one reason why putting high morale commanders into the most senior posts can be a good idea).
For leadership checks, basically the corps commander is tested. If they pass then the planned action (allocate SU, supply etc) happens, if they fail then the next up the chain is tested. Each step back from the front line, the actual leader ratings are reduced but if you have good commanders at each stage, you have a very high chance of passing the checks.
There was a rule in WiTW when it was first released that encouraged keeping Corps at 1 hex - *I think* this was removed some time ago.
Sounds like the system in Steel Panthers WW2. Does every leader only get 1 failure per turn? Or can they keep doing checks to compensate for the failures of every subordinate? In SP, if the captain of a company fails in his attempt to provide Rally for an infantry squad, that's it, he can't try to help any more subordinate units that phase.
So if Eisenhower fails the roll to help one Corps, can he still try to help other Corps?
< Message edited by Lovenought -- 12/8/2017 12:24:00 AM >