I am pretty strongly anti-declawing. BUT:
We live in an imperfect world full of people who may or may not necessarily be willing to put themselves out to deal with an inconvenient animal, and also there are some few rare cats out there that are reeeeeeaaaaaal hard to find anyone willing to put up with in their clawed state (even with the *best* training and cat trees and so forth)... and I think that if a person has exhausted all of what they see as their options and is GENUINELY going to have the cat put down if it's not declawed, probably it is reasonable to try declawing first.
Yeah, some cats have problems with it. I've seen cats get very schizzy and shy, become permanently sore-footed, be unable to escape from dogs, etc. But even so, there seems to be pretty reasonable odds for *not* having lasting problems from declawing, and I think (yes, I am guessing and projecting, here) that most cats would rather be lacking in front claws than euthanized.
In a perfect world there'd be homes enough to go 'round for ALL cats, and you could just find a cat another more suitable home if he didn't "work out" in yours and you'd reached your limit of things you'd try to correct the problem.
However, meanwhile back in the REAL world...
JMHO,
Pat, who just finished building *more* outdoor run (including a bridge) for her cats on account of Mojo has once again stopped eating, arrrrgh.