However, the skills are not reinforced or even practiced really. It is not as easy to conduct EW against GPS as you would think, at least not military specific capabilities. There are contingencies and capabilities in place for that.
Bigger concern would be the GPS satellites being destroyed altogether.
Which is also why when you hear news reports about China or the US destroying their own satellites using ship launched missiles, the message intended to be conveyed is more than meets the eye.
Those demonstrations are really about telegraphing to adversaries what you can/would do in the event of a conflict.
