One of the last lines in Chinatown is "As little as it takes." What the heck does that mean??? I've gone over the last scene a dozen times, and I can't seem to get it in context.
I think it means that the more the Chinatown detectives try to do, the more trouble they inadvertently cause. In an earlier scene where Evelyn asks Gittes what he did in Chinatown, he says something like "as little as possible," and then explains how it was hard to tell the victims from the perpetrators because of all the different languages/dialects that were spoken there.
It's a reference to an earlier line in the film where Gittes was talking about when he was a detective. When asked what he did in Chinatown, his response was "as little as it takes", meaning that the police in Chinatown weren't particularly interested in getting involved in crime solving. Hence, "Forget it Jake. It's Chinatown." means he should just walk away because nothing is going to get done.
Brad
EDIT: Ben responds while I'm typing... making me redundant.