1.I think GPS spoofing is much more difficult than jamming.You need to be able to the track the victim aircraft so that you can radiate it with a false position that convincingly deviates from the true track. That needs an independant track and a GPS simulator ---band of skilled engineers required and then only kill one target. Jamming you can do with a load of thugs.
2.Cancelling e-Loran was a disaster in my view,but it was a presidential directive (There are plenty of other things Obama could have cancelledor not even started)
3.The main jamming threat(by a load of thugs) will come in10-20 years time when the world is basing traffic capacity on functioning satnav and ADS-B, and by that time we must have a "get you out of trouble " back up.
Keith