If everything is fine, but you jack up one of the front wheels, start and idle the engine, put it in first and slowly engage the clutch, the wheel that is off the ground will spin and the front wheel on the ground will not move. It's the nature of the differential built into the transaxle. The broken axle (I assume a completely broken CV joint) allows any torque from the engine to go into spinning the broken axle. If the axle was not broken, there's no way any part of the axle can rotate and the wheel would not also move.You can get a limited slip differential to put in there to make it harder for one axle to spin without the other axle also spinning, but for most drivers on roads they are not needed.There's probably a write up about differentials on howstuffworks.com somewhere EDIT -
http://auto.howstuffworks.com/differential.htmSucks, because there's not much you can do to the the car to move with one of the axles broken. If there is any good news in that, then at least the clutch is still grabbing enough to spin the broken axle, and also, I think you are the first here to have broken a drive axle.