The ability to disable cell phones is already there and used in most of the rest of the world. All the carriers have to do is to ban the IMEI number of the phone when it is reported stolen and the phone can't be activated on the network. Yes, the phone isn't wiped, but it removes the primary cause of phone theft, which is selling them (since people will not be able to activate and use the stolen phone). This is used to great success almost everywhere except for the US where the carriers refuse to do it. We don't need something new, we just need the carriers to do the same thing carriers all over the world are already doing.
My guess is that carriers don't want to halt phone theft since it is a money boon for them. If someone's phone gets stolen, then they have to buy a new one from the carrier at full price, and the carriers make more money that way. If they start banning IMEI numbers and phone theft goes down, they don't get than extra money in their pocket. All the government has to do is mandate that the carriers not allow stolen phone's IMEI numbers on their network and everything takes care of itself.