Time to pull out my mask with the shifting patterns...
There are problems with this. To say the least.
A. It's aliens. Invading. Which is the plot straight out of 50s B-movies and then recycled after the seventies. People will fall into three categories: Those who think it's a hoax, those who don't believe in aliens, and those who fall for it and really aren't going to be especially economy-useful.
B. You create an economy based around arsenaling up for war. So tremendous effort and resources going into military hardware. Whereas today, it's all complex enough that it's all about development anyway, and a whole bunch of extra rivet-knockers is really not going to do much good at all, because so much of the procedure is specialized. Unless we decide to mass-produce WWII technology, for some reason, which wouldn't surprise me the way this is going.
C. Everybody is up-arsenaling for WAR. A fictitious war with a bubble that's going to burst and leave everybody with a surplus of military hardware and preparations...and nothing to do with it. You know what happens next? WAR! Starts with the little guys trying to duke it out for territory, followed by bigger powers stepping in, and suddenly you find that you've ordered World War III to-go.
D. It's an incredibly focused economy, with all resources going into immediate, short-term areas and forsaking everything else almost entirely. Of course, considering who's saying this...
E. It involves a massive conspiracy involving the world's governments engaging in broad deception in order to fuel a war-based economy so that... Actually, you know what? I don't know what the problem with this is. It makes perfect sense! Start with a state of emergency, invoke martial law, get everybody working for you, and BAM! Absolute control and dissolution of individual freedoms. What could be better?
F. When we find out it's all a big joke, there WILL be riots. Likely on a broad scale. Likely involving the people utilizing all those lovely machines they've been building. Today's forecast is mostly rioting, with a high chance of revolution.
G. He's a Keynesian. Which means he's a drooling moron, as otherwise evidenced. Why are we listening to this idiocy, again? OH WAIT!