This could be the most important metric heading into tomorrow's midterm elections: Most people think Republicans will take control of the House, according to CNN's most recent polling.

51 percent said Republicans will control the House in 2011, while 36 percent said Democrats would retain control. 8 percent suggested split control, while 4 percent had no opinion.

The results come from CNN's latest national telephone poll of 1,006 Americans, and they show a drastic shift from August, when 47 percent said Republicans would take over and 45 percent said Democrats would remain in control.

Here's how Opinion Research, which does CNN's polling, phrased the question: "As you may know, the Democrats currently control the U.S. House and Senate.  Just your best guess -- after the congressional elections this November, do you think the Democrats or the Republicans will control Congress?"

Expectations influence group behavior, and this impression seems like--having already been caused by measurements of the "enthusiasm gap," which have shaped media commentary on the elections and have most likely fed these respondents' sense of what will happen--it will itself cause Democratic enthusiasm to spiral further.

If you're a Democratic-leaning independent, not a very political person but with liberal sentiments, and you expect Republicans to take over the House, you're probably less likely to vote as a consequence. You're disgusted with all the negative ads you've seen; you don't like thinking about the pending Republican subjugation that, polls and the media tell you, is a foregone conclusion; it's 6:30 a.m., not 7:15, and your alarm is buzzing earlier than usual because you set it with the intent of voting before work; your first association when you think about the polling place is the miserable state of these horrible elections and how it's a terrible year to be a liberal; you want to hide from this harsh reality and go back to the dream you've been having, in which you canoed down the Missouri and ran into the neighbor girl, who sat atop a vessel that resembled a Mardi Grad float; the buzzing continues, but you're getting used to it; your eyelids dim; you can see her throw the beads; you catch them in your outstretched hand as she waves; you drift back into non-voting half-sleep; your unconscious fingers hit snooze. CNN predicted it.