Am I wrong to refuse to "help" the Department Idiot?

[BiggJawn]

There's this guy who's in charge of another section of my department who, frankly, I wonder how he gets through the day without drowning in his own spit.

His alligator mouth is always making promises that my section's canary ass has to deliver on, and frankly, I'm sick of it. The "Culture" of the place seems to be "We cover-up for our idiot cousin and make the whole department look good" and I don't wanna play along anymore.

This guy makes almost TWICE what I do and knows HALF (or less) than I do, but I'm expected to do his thinking for him and save the day so he looks like a furking Hero and I've had it.
One of the other techs, an "Old Timer" was telling me how I should have found out what a client needed and figured out how to supply it instead of letting the Village Idiot look like bozo.
I told him that since this guy exploited a "falling down" of mine this past year in order to cover his own ass and I got hung out to dry with a nasty letter in my file and NO raise that I didn't feel like I owed him any "favours".

This didn't go down too well.

What say ye, fellow Evil DU'ers? Am I wrong to give the village idiot enough rope to (finally) hang himself with?

Should I continue to wipe his ass and mop up after him for "the Good of the Department"? He had no trouble throwing ME to the wolves when I was down and he needed a diversion.