Wouldn't taking fingerprints at passport application time deter some of this passport identity theft? If the prints don't match, the entry is denied.....or is that too complicated? I realize it's not foolproof, but would certainly nail some of the attempted fraudulent entries.
One would think checking fingerprints would be good; of course one would actually have to CHECK the fingerprints. That takes time. That takes money. That takes manpower. It should be done.