Can the Polearm Master bonus attack only be used after the main attack?

Question

The first benefit of the Polearm Master feat says (PHB, p. 168):

When you take the Attack action and attack with only a glaive, halberd, quarterstaff, or spear, you can use a bonus action to make a melee attack with the opposite end of the weapon.

Does this additional attack clearly occur after the attack with the main weapon? Or is there a time to use it between the attack being "declared" and resolving the main attack?

Background/motivation: I would like to attempt the following:

1. Announce I am attacking Bandit Keith;
2. Use the bonus action to attack with my halberd's shaft, with a Tripping Attack maneuver;
3. Assuming success on the attack / STR check, attack with the halberd blade at advantage;

While that appears to fit how the flow of a fight works in my head, the word take appears a bit ambiguous to me if I wish to argue from RAW. If an action is taken, does this mean it must be completely resolved?

Answer 1

After the Attack action is complete.

Crawford has explained the intent of the rules:

Clarification about bonus actions: if a feature says you can do X as a bonus action if you do Y, you must do Y before you can do X.

In this case, your feat says:

When you take the Attack action and attack with [...]

So you need to declare you're attacking Keith and conduct your attack(s). You can then use your bonus action attack with a Tripping Maneuver. After that, feel free to Action Surge and (hopefully) slam a prone Keith!

Consider that, if you could do this the other way around, you'd break the logic. If you did a BA attack first and killed your target, you would finish combat and no longer have anything to attack with your action, which would break the when you take the Attack action and attack condition.

This is very similar to the Shield Master bonus attack, Eldritch Knight, and Crossbow Expert rulings, which have the same wording.

When you use the Attack action and attack with a one-handed weapon, you can use a bonus action to attack with a hand crossbow you are holding.

If you take the Attack action on your turn, you can use a bonus action to try to shove a creature within 5 feet of you with your shield.

Quoting Protonflux's answer from the Crossbow Expert question:

While this is perhaps not as clear as it could be, the order is implicit in the logic of the description: When you take the attack option (this must happen first for the condition to be satisfied) you can use a bonus action (therefore this must happen after taking the action).

It would perhaps be better if it had been written: "then you can use a bonus action", but omitting the "then" does not change the fact that there is a when condition.

Answer 2

The order is unimportant, you take both attacks

When you take the attack action, you can choose which of the attacks is the 'bonus' attack, and you choose when it occurs. Your are still taking the Attack action so you'll do both attacks.
This is directly supported by the rules on PHB page 189.

You choose when to take a bonus action during your turn, unless the bonus action’s timing is specified, and anything that deprives you of your ability to take actions also prevents you from taking a bonus action.

The timing is not specified. For an example of when the timing is specified, see the Monk's Flurry of Blows feature says, which specifies "after"

Immediately after you take the Attack action on your turn, you can spend 1 ki point to make two unarmed strikes as a bonus action.

Related Q&A are here.

The polearem master has no restriction; when does not mean immediately after. If the Polearm Master feat had specified "immediately after" (as was done with the Monk) that would be different. Such required sequencing was not specified.

Some notes on RAI and the confusion

That Jeremy Crawford has waffled on how the choice of when to take your bonus action influences feats like Shield Master (after two years of adhering to the original basis) is an unfortunate case of putting the twit into Twitter and thereby abandoning the core guidance for this edition of using plain English to interpret the rules.

His original point on sequencing was made back in 2015.

@JeremyECrawford
Jan 21, 2015
As with most bonus actions, you choose the timing, so the Shield Master shove can come before or after the Attack action.

Two years later, for whatever reason, he changed his mind but the real problem with his waffling is that the rules as written allow for the choice of what happens in the combat turn - when you apply your bonus action - unless otherwise specified. (An interesting analysis of that is here).

So what do I do?

This brings us back to "rulings versus rules" - I suggest that you work with your DM and arrive at that which makes the most sense at your table. And once the DM rules on it, go with that and don't look back. If you have read a lot of J Crawford tweets over the years, as I have, you'll find a common refrain from him along the lines of: whatever gives you the most joy at your table. Work with your DM.

Answer 3

Much of the rational for disallowing these types of bonus actions to occur before completing the requisite action rests on the consideration that some circumstances may remove the qualifying action from coming into play. For example using a bonus action shield bash to shove your only opponent over a cliff removes the opportunity to follow up with an attack action. I don't find this to be sufficient rational to restrict the order of application. It seems enough that by using such a bonus action you have effectively committed to using your action in the requisite way. If you can no longer do so or choose not to, you simply lose your action. That is the cost of using a bonus action that requires your action to be used in a particular way. This seems to me to be the fairest application of these rules and affords the player choice without undue benefit.