A lawyer who has JUST passed the bar does indeed have a better chance of getting hired in a better position at a better law firm if he went to a law school with great credentials.
A lawyer who has JUST passed the bar but went to a lesser law school will have to be awfully damn impressive or will have to work their way up the ladder at smaller firms and gain a reputation of having a great case record.

Once a lawyer has a great case record, there will be less people who will care which school the lawyer went to. But in the beginning, it does matter.

I'd like to add Stanford into the discussion of top US law schools.