... maybe another way to illustrate it? Mike Luckovich's cartoon for today:
In Luckovich's defense, most of the time political cartoonists, like political speakers, are working with the stock array of images/concepts already in people's minds. Only the best -- cartoonists or speakers -- in their best moments introduce new images that really stick. You can't expect that from anyone, in any field, on a daily basis.
On how Paul Krugman might have altered this cartoon, here; for the special circumstance in which the boiled-frog metaphor is true, here; for why boiled frogs are like WWE-style pro wrestlers, here; from Wikipedia, here. Complete boiled-frog collection here.
CNN/Fortune lapsing in the same way, here. Interesting discussions of how and whether to use an image you know is not literally true -- like "ostrich with its head in the sand" or "camel's nose under the tent" -- but that gets a point across, here (from Mark Liberman of Language Log) and here (from Kevin Drum of Mother Jones) and here (from Joe Romm of Climate Progress).
A reader in England writes with a suggestion for a substitute image that is more factually defensible. (Hint: based on the unforgettable opening scene of Ian McEwan's Enduring Love. If you've read the book, you know the image.) More on that soon -- plus! a reader's nominee for the next most inaccurate and overused rhetorical image. Coming soon. For now, the main point of Luckovich's cartoon is right. Thanks to reader J.S.