Can I combine Path of War maneuvers with Power Attack?

Question

Can I combine a strike with combat expertise and/or power attack?

Strike: A strike is a maneuver that allows a special attack. A martial disciple who slays a wyvern in a single blow is using a strike. A strike imparts some bonus or advantage over a standard attack, such as extra damage, or an additional effect such as blinding a foe.

Strikes almost always require a standard or full- round action. Most involve a melee or ranged attack as part of completing the maneuver. If the attack hits, your opponent takes normal melee or ranged damage, as well as suffering the effect of the strike. When making a strike, you use your base attack bonus, all attack and damage modifiers, weapon damage, and so forth, as normal. You can make a critical hit with a strike, but you do not multiply extra damage from a strike when calculating the critical hit damage. It is treated just as extra damage from another special ability would be (like deadly strike damage or damage from a flaming weapon).

Because strikes require a specific form of attack, you cannot benefit from spells or effects that grant extra attacks when making a strike (such as the haste spell or a speed weapon). You are not taking a full attack action when you initiate a strike whose initiation action is 1 full round, unless otherwise specified in the description. Also, you cannot combine special attacks such as disarm or sunder with strikes, unless stated otherwise in the maneuver's description.

Source

Answer 1

Power Attack: Yes

Power Attack's only limitation is as follows:

You must choose to use this feat before making an attack roll, and its effects last until your next turn. The bonus damage does not apply to touch attacks or effects that do not deal hit point damage.

As long as you're making an attack roll at some point, you can turn it on. Most (but not all) strikes require attack rolls, so they work just fine.

Combat Expertise: Maybe

Combat Expertise's wording is slightly different:

You can only choose to use this feat when you declare that you are making an attack or a full-attack action with a melee weapon. The effects of this feat last until your next turn.

There's some ambiguity about whether or not this means this:

... when you declare that you are making an attack or [making] a full-attack action with a melee weapon.

or this:

... when you declare that you are making an attack [action] or a full-attack action with a melee weapon.

The first case would allow Combat Expertise to be activated whenever you make any kind of attack with a melee weapon. The second case would only allow it to work when you specifically take the attack action or the full-attack action. Grammatically, it could be read either way.

Sadly, there is no FAQ question or answer on this topic, nor any developer commentary on it that I could find. There's a lot of debate and discussion about how it's supposed to work, though!

Interestingly, the wording from the 3.5 version of Combat Expertise said this:

When you use the attack action or the full attack action in melee...

Which is entirely unambiguous, leading me to wonder if Paizo altered it to make it work on all attacks, instead of just the attack action. However, in the absence of any official word stating that, we can't conclude anything, and how it works is entirely up to your GM.

Thankfully, in the absence of any way of clearing this up using the RAW on Combat Expertise, we can turn to the RAI on strikes to answer the question:

Strikes are meant to work with Combat Expertise.

The wording is ambiguous about whether or not it works with attacks or just with attack actions, but unless the feat is later errata'd or FAQ'd to state one way or the other, the intent is that the more liberal reading of it is correct in the context of maneuvers.

Source: I'm the editor for Path of War: Expanded, and asked the writers.

Answer 2

Power Attack: yes

First of all, let's look at the benefits:

You can choose to take a –1 penalty on all melee attack rolls and combat maneuver checks to gain a +2 bonus on all melee damage rolls [...]

So far, so good. There are no limitations to specific types of attack, it's all melee attacks, and "(m)ost (strikes) involve a melee or ranged attack as part of completing the maneuver." How you get to make these melee attacks, i.e. whether it's a strike involving a melee attack, or the Attack action, or the Full Attack action, is irrelevant except for the limitations mentioned in the feat (e.g. no touch attacks).

Combat Expertise: maybe

While Combat Expertise starts with the same wording as Power Attack, there is an additional limitation at the end of the benefits section:

You can only choose to use this feat when you declare that you are making an attack or a full-attack action with a melee weapon.

As KRyan points out, there are two readings to this, and whether or not Combat Expertise is allowed with strikes depends on this reading.

1. "making an attack with a melee weapon or making a full-attack action with a melee weapon"
   In this case, Combat Expertise is allowed whenever you declare that you are going to make a melee attack, similar to Power Attack.

2. "making an attack action with a melee weapon or making a full-attack action with a melee weapon"
   In this reading, it specifically only allows you to benefit from the feat when you use either of two defined action types: The standard action "attack" and the full-round action: "full attack".

   Strikes are neither of these, so you can't use Combat Expertise:

   You can't combine options that modify attack actions with standard actions that aren't attack actions, such as Cleave.

   Note that when using this reading, Combat Expertise is also not usable with things like Cleave, Spring Attack, the free attack granted by Spellstrike, Whirlwind attack, and so on.