"...another career politician.." Who were up you expecting, Leon, a lollipop lady?
I've no idea whether he'll be any good but if you're implying previous military service is essential, bear in mind some of our most disastrous Defence Secs have been so qualified. Dennis Healey for instance, late of the Royal Engineers pretty much dismantled the Services on his watch. Not just the high profile scrappings of most of our carriers, TSR2 and the F111, but a thorough neglect of the basics. He left our submarines to all intents unarmed, with torpedoes capable of less than half the speed of Russian subs.