Can you target an already stunned unit with Zenith Blade to get the move effect, and will Radiant Dawn trigger to give an extra buff?

Ruling: You can target an already stunned unit with Zenith Blade and still get the move effect, but Radiant Dawn will not trigger because the stun part resolves without doing anything (the unit is already stunned).

Nuances:

• Triggers that require a target to be stunned won't activate if the unit is already stunned