Krugman's theory has been tried before. In France. Read the (free) ebook Fiat Money Inflation in France to see where that ended. Government stimulus at first appeared to work great (sound familiar) then, like gasoline on a fire the effect died away. What to do? More stimulus! This also appeared to work (only for a shorter amount of time), then, guess what, no more gasoline. More stimulus! Even less effective. On and on it went until the government collapsed and Paul Krugman - oops, I mean William Law, author of the grand inflation - was run out of France. This is where Krugman's theories would lead us.
Of course, since Mr. Krugman has a nice house on a Caribbean island and spends his days drinking Mai Tai's on the beach while telling us how to destroy ourselves, he probably will not mind being run out of the country.