Can you choose to use abilities like Stunning Strike or Divine Smite after rolling damage?

Question

There are certain abilities that require you to first make a hit, then you can choose whether or not to use that ability.

Two examples that I can think of are a monk's Stunning Strike and a paladin's Divine Smite (there are others, but I won't enumerate them all here; an answerer is welcome to if they wish to do so):

Stunning Strike
Starting at 5th level, you can interfere with the flow of ki in an opponent’s body. When you hit another creature with a melee weapon attack, you can spend 1 ki point to attempt a stunning strike. The target must succeed on a Constitution saving throw or be stunned until the end of your next turn.

Divine Smite
Starting at 2nd level, when you hit a creature with a melee weapon attack, you can expend one spell slot to deal radiant damage to the target, in addition to the weapon’s damage. The extra damage is 2d8 for a 1st-level spell slot, plus 1d8 for each spell level higher than 1st, to a maximum of 5d8. The damage increases by 1d8 if the target is an undead or a fiend, to a maximum of 6d8.

Neither of these abilities specify whether or not you can declare these abilities before or after resolving damage. There are other abilities that say "after you know the roll, but before the DM tells you whether it was a success" or similar wording, but that usually relates to the d20 roll, not damage rolls.

Question

Am I able to roll to attack, hit, roll damage, then make the decision as to whether to spend resources on an ability like Stunning Strike or Divine Smite? If I am allowed to do so after rolling damage, what about before or after the DM tells me the effects of the damage (e.g. did it kill the enemy or not)? Intuitively, it feels to me as though the answer is before damage only, but I'm not seeing anything that implies that this is the case RAW.

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If this is something that isn't specified and is up to the DM, then so be it, but I'm specifically interested to know if there's any general rule anywhere that resolves this RAW, or whether I'm just not reading those abilities quoted above correctly (or whether there's another, similar ability that does make it a bit more explicit, and I just chose poor examples).

Answer 1

No

Trigger interpretation

One reason is the conditional trigger in the wording you have quoted.

when you hit a creature with a melee weapon attack

Thus, the trigger to your ability is hitting the creature. There are two ways you can interpret this trigger:

• You must take the (re-)action immediately after the trigger.
• Or you don't.

My "normal English reading" is the first bullet. You must take the action immediately after the trigger, i.e., immediately after hitting the enemy. Once you have rolled damage, the "last event" that happened was not the hit, but the damage being dealt, and therefore you have missed the timing on using your ability.

For why I don't think the second interpretation is sound, I will use a slippery slope: if you allow the Divine Smite to be rolled after other events have happened, why stop at after the damage being dealt? Why not, after 3 rounds, "Hey, remember that guy I hit 3 rounds ago with my melee weapon attack? I will now roll the Divine Smite damage!"?

Damage Roll interpretation

Another argument that can be made is that when you make the attack, this is what happens:

You make the attack roll. On a hit, you roll damage, unless the particular attack has rules that specify otherwise. Some attacks cause special effects in addition to or instead of damage.

Each weapon, spell, and harmful monster ability specifies the damage it deals. You roll the damage die or dice, add any modifiers, and apply the damage to your target. Magic weapons, special abilities, and other factors can grant a bonus to damage.

And, from your own wording

before or after resolving damage

This, at least to me, implies that you roll the damage for the attack only once. Once the damage is resolved, it is resolved, and no extra damage can be added to that attack. Divine Smite specifically states that the damage is "in addition to the weapon’s damage", again implying that the damage is part of the attack, and therefore, if the damage of that attack has already been resolved, then the damage can no longer be changed. Furthermore, the highlighted part of the text also implies that effects such as Stunning Strike, which happen in addition to the damage, should be resolved as you roll damage, not afterwards.

In this case, I would say being able to "break up" the damage rolls and use a feature in the middle of it is not allowed. While this is not something that is explicitly stated to be impossible in the rules, it is not explicitly allowed either. Since it is something very unusual, if it was allowed, I would expect it to be white-listed, not the other way around.