He will be spending less on everything.
Yep. Production creates demand. Washington [Democrats and Republicans alike] claim it's the other way around.
They are wrong. There can be no demand without production. Attempts to goose the economy by encouraging consumption are and always have been failures.
Now, you won't like this part. Defense spending is government spending and all government spending [even on projects we approve of such as defense] is a drain on the private economy.
Defense spending is necessary, but it does not create economic growth. It reduces it.