Dispel Magic vs. Magic Resistance

In Session 160, the PCs tripped a Dispel Magic trap that stripped off a lot of magic. Two of the PCs have Improved Magic Resistance - Gerry and Bruce. The players wanted to know if their magic resistance protected the spells cast directly on them (such as Gerry's Levitate and Invisibility) or on items they carried.

After a few minutes of discussion - worth the break in play - I ruled that it would not, largely because I saw way too many abuses if the answer was "yes." Also, the weird loophole of magic being "safer" from anti-magic countermeasures while in the hands of anti-magic characters.

But I said I'd ask Sean "Dr. Kromm" Punch. He gave me his permission to post our discussion here. Here is his original answer, and an answer to a followup. We had further discussion but it isn't really germane, I was just talking about what I'd do in Felltower and he explained his take on it. That's another post entirely.

***

> The question was, would their MR add to the rolls of spells cast on
> them vs. the Dispel Magic?

I don't see why it would. It seems beyond weird to me that anti-magic
like Magic Resistance (any origin) would actually *help* magic not be
wiped out . . .

Subjective judgments aside, I'd say "no" because:

1. Magic Resistance (again, regardless of origin) protects a person,
while Dispel Magic isn't cast on a person but on an area.

2. Inasmuch as Magic Resistance helps against Area spells, it affects
those that give *people* a chance to resist. Dispel Magic doesn't let
people resist -- it lets *spells* resist.

3. Magic Resistance actually says: "Magic Resistance only interferes
with spells /cast directly on you./"

(The opposite question interests me more: "Would MR make it easier for
Dispel Magic to remove spells from people who have it?" As MR makes it
harder for magic to "stick," I could support a GM ruling that it makes
it easier for Dispel Magic to "scrape" spells off of people. It would
seem much more intuitive to me if it worked in favor of Dispel Magic,
anti-magic being complementary to other anti-magic.)

> My ruling was that Magic Resistance/Improved Magic Resistance
> doesn't affect the spell vs. spell contest, and wouldn't affect
> Dispel Magic vs. the Continual Light items they carried, either.

Agreed.

> Anyway, could you answer these questions, and can I have permission
> to quote you, unedited, on the answers and post them on my blog?

Of course! Quote everything below the "***" if you want.

> 1) Does Magic Resistance - either from the advantage or the spell -
> affect the contest of spells of Dispel Magic vs. a spell with the
> Magic Resistant character as a subject?

No.

> 2) Does Magic Resistance extend to items carried by the resistant
> character?

Only inasmuch as noxious spells that affect carried gear are protected
by your Magic Resistance. So, to avoid "I'm casting Flaming Murder on
his shirt, not on him!" cheese, if you have MR, it should (for example)
subtract from Disintegrate or Stiffen cast on your armor, Apportation
cast on your weapons, and so on. However, *spells on your gear* are not
*your gear* . . . too bad for them.

> 3) Does any of this change if the Magic Resistance is Improved,
> Switchable, or put on by the spell Magic Resistance?

Nope.

SP.

Next email:

> Logically, then, helpful spells cast on equipment - Flaming Armor,
> Lightning Weapon, etc. - should equally be resisted by the bearer's
> own magic resistance. Does that follow?

"Logically" and "spells" don't play nicely in the GURPS magic system,
but . . .

*In principle,* it would be fair to rule that way. People protest the
downsides to MR: "Wahhh, it's hard to be healed or buffed, and I can't
use potions!" However, there are so many cheesy workarounds (read on)
that MR's intended downsides -- which keep its cost at 2 points/level
-- almost don't matter.

*In practice,* gamers will do this:

"I set down my armor and weapons and walk away."
"I cast buffs on his armor and weapons."
"I go get my stuff back, with the buffs."

There's no rule in GURPS that would cause MR to break the spells under
those circumstances. That would be an annoying rule, to be honest, and
I'm not claiming that we need one. It would add too much dice rolling,
most of it adversarial to the players.

So, I'd just ignore the logical ramifications. Enemies won't set gear
down for you and let you cast Disintegrate, so it's simplest to say,
"Yes, MR affects that."

Allies totally will do things like that to get buffs, so while in the
corner case where you don't have time for the little dance and/or your
wizard can't buff you each morning and maintain it for free all day,
you might have to worry about MR . . . that isn't normally going to be
a concern. Ockham's Razor leads me to say, "Cut out the middleman and
just say MR doesn't affect buffs on gear."

It wouldn't be the first or even 10th place in GURPS where beneficial
and hostile magic use totally different rules.

SP.

As I said earlier, I'll do something differently, a bit, in Felltower - but then again we also run Magic Resistance a little differently, so it's not going to change much.