Can sacred flame target someone that is behind total cover?

Question

One of the rules for targeting spells in the Player's Handbook says that spells must have a clear path to the target:

A Clear Path to the Target

To target something, you must have a clear path to it, so it can't be behind total cover. If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.

And the description for total cover says:

A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle.

However, the spell sacred flame says that the target "gains no benefit from cover". Does this mean sacred flame can target someone that is behind total cover?

Answer 1

RAW: Total cover stops sacred flame

Sacred flame does not state that it ignores cover, only that:

The target gains no benefit from cover for this saving throw. (PHB 272)

and thus does not overrule the general rule that:

To target something, you must have a clear path to it, so it can't be behind total cover (PHB 204)

If you cannot target someone they do not have to make a saving throw and thus whether they get a bonus to it or not is irrelevant. In line with this, total cover does not provide any bonus to saving throws, in contrast with other levels of cover:

A target with half cover has a +2 bonus to AC and Dexterity saving throws.

A target with three-quarters cover has a +5 bonus to AC and Dexterity saving throws.

A target with total cover can't be targeted directly by an attack or a spell, .. (PHB 196)

This feature is basically the single-target version of "spreads around corners".

Question of RAI

In this podcast Jeremy Crawford stated that sacred flame completely ignores cover (eg. it can be targeted through windowpanes). He is the lead rules designer and his statement might reflect what the designers have originally intended, even though that is not what appears in the book. As always, the DM can make a ruling on this matter however they like, but to this day this alternative interpretation has not appeared in any written errata.

Answer 2

Yes, as long as they can see the target (according to Rules as Intended)

Jeremy Crawford confirms that this is indeed the intended interpretation of the spell's effects on the Jan. 19, 2017 episode of Dragon Talk ("Wolfgang Baur on DMing for Girl Scouts"). Starting at 36:20, he says (transcription done by me):

There are spells that create exceptions to this rule about needing a path clear of obstruction. One cantrip [that breaks] this rule is sacred flame. Sacred flame is one of the low level spells that has this text: "The target gains no benefit from cover for this saving throw." [...] So, they're getting no benefit from cover [...] and that includes total cover. So sacred flame is one of the few spells that allows you to target somebody even if they're behind total cover. [...] You can be looking through the window in the tower and cast it on someone outside.

So, mechanically, this means that, as long as the caster can see the target, they can target them regardless of how much cover they have. Since total cover is a type of cover, it also is ignored by sacred flame.

For comparison, the normal rules for targeting dictate that if a spellcaster is behind a sheet of glass with no possible line of effect to the target, they cannot target them with a spell.

Narrative explanation

Jeremy Crawford continued on from the above provides some reasoning behind the spell and why it was written as it is. While not vital for a mechanical understanding of the spell (the above logic should be more than sufficient), it is interesting nonetheless.

The narrative reason for that, the reason I wrote it that way, is that sacred flame is coming down from above the person. The idea is the cleric is calling this divine energy down on the target and it is not actually shooting out from the cleric, it's coming down. [Which is an exception] and in the game the exceptional always beats the general.