Does a target affected by the Compulsion spell have to take the Dash action?

Question

The description of the compulsion spell states:

[...] Until the spell ends, you can use a bonus action on each of your turns to designate a direction that is horizontal to you.

Each affected target must use as much of its movement as possible to move in that direction on its next turn. It can take its action before it moves. After moving in this way, it can make another Wisdom saving throw to try to end the effect.

A target isn't compelled to move into an obviously deadly hazard, such as a fire or pit, but it will provoke opportunity attacks to move in the designated direction.

Reading the spell again it says they can use their action before moving but what if they don't? Do they then have to dash to use "as much of [their] movement as possible"?

What about rogues? If they are affected by it, do they have to use their bonus action from the Cunning Action feature to Dash? The spell only permits their action, not their bonus action.

Answer 1

The creature(s) does not have to dash

Actually, compulsion seems quite carefully worded around to avoid that. Let's look at a couple of points:

• If the spell forced taking the Dash action it would say so. For example, fear states:

  a creature must take the Dash action and move away from you by the safest available route

• Compulsion explicitly states the creature can use its action before moving:

  It can take its action before it moves.

  If it was forced to take the Dash action no such clause would be necessary.

• Compulsion specifically forces to use their movement to move in a direction, not to move as far as possible during their turn. Unless the creature chooses to use any of their action, bonus action, or other resources (which the spell does not compel them to do) their movement is only equal to their speed.

Answer 2

The creature is not compelled to gain additional speed or movement

Compulsion forces the creature to "use as much of its movement as possible". The Dash action does not involve using movement; rather, it allows a creature to "gain extra movement". A compulsion to use all your movement does not imply a compulsion to also gain movement so that it can also be used. If it did, would you force a wizard to spend their action casting haste or fly on themselves so that they can better obey the compulsion? Would a monk be required to spend a ki point on Step of the Wind to dash? Must a druid wild shape into an eagle?

You are confusing "use as much of its movement as possible" with "move as far as possible". The latter interpretation quickly opens up a Pandora's box of ambiguities, as shown in the above examples. At a more basic level, it violates the "no secret rules" principle of D&D 5e. Not to mention, it contradicts the text of the spell itself, which explicitly gives the creature the option to use its action.

To be clear, if you do decide to take an action that gives you extra movement, you are then compelled to spend all of that newly-gained movement moving in the designated direction. However, nothing obliges you to take any such an action, including the Dash action.