CC Writer, you're welcome. I first read of the EMP threat in Helen Caldicott's book Missile Envy some 30 years ago and since it hasn't been front and center since didn't think it posed much of a real threat.
As for my comment re Gingrich i saw his - repeat again, as you did
as at least implying that Trump wasn't taking it as a ultra-important matter either. You'd agree that Trump's words mean little, at least most of the time.
It does make sense that Trump would say he thought it was important (especially in an election campaign) since it's scary-scary stuff, though there are much less expensive and risky ways to knock out power grids.