Does the buff bonus from Stand United stack if you play multiple copies in the same turn?

Ruling: Yes, the "Buffs give an additional +1 [Might] to friendly units this turn" effect from Stand United does stack. Each copy of Stand United you play creates a separate instance of this duration effect that lasts until end of turn.

Sequence:

• First Stand United: All buffs give +2 Might total (+1 base +1 additional)
• Second Stand United: All buffs give +3 Might total (+1 base +2 additional from two instances)

Nuances:

• You still cannot place multiple buff counters on the same unit (only one buff per unit).
• The stacking occurs because each spell resolution creates a new, separate duration effect, not because you're reapplying the same effect.