I mean, if Krugman gets any more depressing, his entire audience is going to go out and hang themselves. Probably why he made his own attempt at humor -- suggesting that a fake alien invasion be staged to unite everybody and get full employment.
Krugman is, of course, being sarcastic about the quality of our current leaders, who seem to be unable to respond to current economic problems like, oh, 1/5th of our children being raised in poverty or 1/5th of our population unemployed or underemployed, and instead engage in kabuki theatre of no import. He's implying that our so-called "leaders" are so stupid and so detached from reality that they'd actually believe the threat of alien invasion and react accordingly. What was hilarous was reading the right-wingers who thought Krugman was actually being serious. You have to read Krugman regularly to "get" his sense of humor, which is very, very dark. If Krugman was any more hangdog, young children would break into tears as he walked by, and dogs would howl in dismay at his passage.
It seems like at least half of Krugman's blog posts could be summarized with a GIF of him banging his head against the wall. There's this constant "Why am I surrounded by idiots?" tone. I know how he feels. Siiiiiiiigh!
-- Badtux the Krugman-watchin' Penguin