We may not know much about "Keynesian economics" (and neither does anyone else: they just plug and pray, literally), but we know one thing: when real disposable personal income drops by 0.2% from a month earlier, and plummets by 2.7% from a year ago, the biggest collapse since the semi-depression in 1974, something is wrong with the US consumer.

And longer-term chart:

Source: BEA