WOTR "A Path of Woes" Card Clarification

By scullbones, in War of the Ring

I have the second edition of WOTR. My question is concerning the "Path of Woes" card. This card lets you attacking an army that is besieging one of your armies with an adjacent army. My question is twofold:

a) Does the army have to be "At War" in order have it attack the army? For example, if the shadow player is besieging the Woodland Realm and Dale is not yet at war, can I use this card to have the Dale units attack the shadow player army?

b) After I play this card, is the free people army that I used to attack the shadow player army required to move into the area it attacked or does it stay where it was?

Thanks,