I would even call the school that offered the full ride and explain that you appreciate their offer and they are a top choice for you, however you are still waiting on hearing from another school so if there is a way that you could get the deadline extended. Wouldn't hurt.
I would also recommend this. Unless we're talking about a school that gives out scholarships like candy, the school obviously really wants you to attend there, as evinced by the full ride. If you call them up and let them know that they're a huge consideration, they're usually willing to give a little leeway with deadlines. And if they don't, it's probably a school I wouldn't consider attending (this is meant for a school that's trying to play hardball with you - accept now or you lose everything! - as the more reputable schools will work with students in these situations).
Just understand that holding off on that decision does affect this law school, as they have limited scholarship funds and want to get that settled ASAP. So while I would be put off by a school that won't budge, I'd expect the deadline to be extended by only a few weeks.
Calling the other schools also won't hurt, and it might get your review accelerated.