Which conditions, if any, prevent or impede the afflicted caster from being able to attack with Spiritual Weapon?

Question

The relevant text for Spiritual Weapon is:

You create a floating, spectral weapon within range that lasts for the duration or until you cast this spell again. When you cast the spell, you can make a melee spell attack against a creature within 5 feet of the weapon. On a hit, the target takes force damage equal to 1d8 + your spellcasting ability modifier.

As a bonus action on your turn, you can move the weapon up to 20 feet and repeat the attack against a creature within 5 feet of it.

Emphasis mine.

It's clear to me that the one attacking, is the one using the bonus action, i.e. the caster (despite the ambiguous use of the word 'attacker', see this Q&A).

I'm trying to figure out, which if any of the conditions listed in the basic rules, either prevent or impede the 'attacker' from using the bonus action. For instance:

Charmed: A charmed creature can't attack the charmer or target the charmer with harmful abilities or magical effects.

Emphasis mine.

It sounds like you would classify the creature using it's bonus action this way as an attack, and/or spectral weapon as either a harmful ability or magical effect that would target the charmer, right?

But 'Frightened' says 'The creature can't willingly move closer to the source of its fear.' which sounds like it wouldn't prevent the spectral weapon approaching?

Which if any of these conditions prevent or impede the afflicted caster from being able to attack with Spiritual Weapon? Are any different than if the afflicted caster made a normal melee weapon attack?

Answer 1

Prevent:

These conditions prevent the caster from attacking a target with spiritual weapon:

• Charmed
• Exhaustion (Level 6)¹
• Incapacitated
• Paralyzed
• Petrified
• Stunned
• Unconscious

Impede

These conditions impede the use of the spiritual weapon attack by giving disadvantage on the attack roll:

• Blinded
• Exhaustion (Level 3)
• Frightened
• Poisoned
• Prone
• Restrained

---

^{1 Level 6 Exhaustion prevents you from doing anything cuz you're dead.}

Answer 2

Here are the conditions that can prevent the caster of Spiritual Weapon from attacking their intended target:

Charmed (by the target)

A charmed creature can't attack the charmer or target the charmer with harmful abilities or magical effects.

As you've noted, the caster is the one making the attack. The spell simply enables them to make this attack against targets adjacent to the weapon. As such, effects that prevent the caster from attacking a target, such as the charmed condition, will prevent them from attacking that target with their Spiritual Weapon.

In general, being charmed by an ally of the target will not prevent the caster from attacking the target, but remember that many abilities that inflict the charmed condition come with additional effects.

Incapacitated (or anything that prevents taking actions)

The Spiritual Weapon attack is a bonus action, and you are only able to take bonus actions if you are able to take "regular" actions. Hence, the caster cannot attack with Spiritual Weapon while incapacitated, or while subject to any other condition that includes incapacitated as one of its effects, including stunned, unconscious, paralyzed, and petrified. Of course, the same is true of any other game effect that incapacitates the caster or otherwise deprives them of the ability to take actions, such as the wave of lethargy at the end of a Haste spell:

When the spell ends, the target can't move or take actions until after its next turn, as a wave of lethargy sweeps over it.

That's all

As far as I can see, there are no other conditions that will prevent the use of Spiritual Weapon, though some may impede it. For example, Spiritual Weapon doesn't require the caster to see the target of their attack, which means they can still use it while blinded, although they will be attacking at disadvantage. Similarly, other conditions like frightened and prone also impose disadvantage on attacks, but do not prevent use of the spell.

Also, if the target is prone, this also imposes disadvantage on the weapon's attacks unless the caster is within 5 feet of them.