I agree that one must stand-up to the likes of Putin.  I question whether this is the correct response delivered in the best manner.  Diplomacy by tweet is questionable.  It's kind of like yelling to one neighbour about the behaviour of another, while the other neighbour is in earshot.  Not really very effective and rather passive aggressive.

As for complaining about military costs via tweet, one cannot govern through pure populism.  There is a limit to being able to use a megaphone to the general public to get the desired response from individuals, companies or other groups.  I guess we're about to find out where that limit is.