Nature abhors a vacuum.

Here's the vacuum:

As the Republican presidential candidates gather this morning in Des Moines for their fourth debate, Iowa GOP voters are expressing limited enthusiasm for the field of current and potential aspirants, according to a new Washington Post-ABC News poll. Their views appear to be a microcosm of GOP sentiment across the country and point to a wide open battle for the nomination.

Former Massachusetts governor Mitt Romney has emerged as the early leader in the campaign for Iowa. But his support is both soft and shallow, suggesting that the Republican race in the state, as nationally, remains extremely fluid.

Just 19 percent of likely GOP caucus attendees said they were "very satisfied" with the field of candidates -- far below satisfaction levels among Iowa Democrats -- and poll respondents were badly fractured when asked to rate the candidates on political and personal attributes.

What will fill this vacuum? Well, Newt thinks he's the guy, but he's not. Newt's a twit. He's the dork who thinks the prom queen wants him when all she dreams of is. . . Jeb. Always, Jeb.

It's Jeb they want. It's Jeb the GOP masses yearn for. It's not Rudy or Fred or John or Sam or Newt, it's Jeb. Jeb is their true love.

I said it here, all the way back in February:

There's a name out there that Democrats don't want to think about that they should be thinking about. That name is Jeb.

It will be interesting to see whether Jeb, feeling the black hole pull of all that pent-up Republican desire can say "no." Don't be so sure. The giant vacuum roars, the airflow becomes irresistable, and off in far Tallahassee, Jeb knows the wind is calling his name.

Ask not for whom the Hoover calls. It calls for Jeb.

On NPR a guy who missed the bridge collapse by a minute. He says, (my best recollection) "If I hadn't brushed my teeth, if I hadn't changed a Band-aid, I'd have been on that bridge."

On MSNBC a girl who was in the car with her mother right behind the famous school bus. They pulled off because they had to pee.

In ancient times people believed in fate or the gods.

When I was growing up everything was upbringing, your environment in the broader sense of the word.

Nowadays Americans tend to believe in free will with quasi-religious reverence. Americans frequently go so far as to deny that any other force but free will can determine the path your life takes.

Of course now some Americans are finding a new, more scientific angle on old-fashioned fate: DNA.

The two cases cited above show that there's another force, inextricably bound up with free will, environment and heredity: random chance.

The guy decides to brush his teeth. Free will. Maybe he had a genetic predisposition to tooth decay. So free will occasioned in part by DNA. Or maybe he'd just been raised well. In any case the effect of his decision to brush his teeth was determined by chance.

You mix together your heredity and your environment. You choose your path. Then you roll the dice to see what really happens.

Brush your teeth, forget to pee before you leave the house, you live. Equally tiny, insignificant factors put other people on that bridge at the wrong time.

Best not to dwell on it.