"Dear Law School X:
Each year, many law schools compete for students like me, and unfortunately students like me can not accommodate all the qualified candidates. I am still very interested in your offer of acceptance, so I have placed you on my Waitlist. My waitlist is not ranked, so unfortunately I can't tell you what your likelihood of coming off the waitlist is. If another Law school that is more qualified than you rejects me, you will move one step closer to acceptance!
Thank you for your interest in me.
It's not so fun when it happens to you."