Politico's Jeff Greenfield looks at the polls showing record-low approval ratings for Congress and similar low approval for Barack Obama and wonders what it means for 2012. His conclusion? Don't expect an anti-incumbent wave to hit next year.

Greenfield says an "anti-incumbent election," where politicians of both parties find themselves in danger of losing, is pretty much a myth.

What happens, rather, is one of two things:

• The angry electorate either isn’t, or doesn’t bother to show up. One particularly egregious example of this misdiagnosis happened in the 1990 midterms. After gazillions of decibels’ worth of such talk, one senator lost his seat. The House reelection rate was about 96 percent.

• The angry electorate does show up at the polls but has figured out who it is angry at, and — fairly or not — punishes that party, while granting more or less full absolution to the other side.

Greenfield does acknowledge that political "rules" do not always hold true. It used to be that nobody won the White House without winning the New Hampshire primary, but that has happened the last three election cycles.