...it seems to me like the broader community that criticizes agriculture is trying to have it both ways.  (This is a criticism of the community, not of this post, or Tom P. in particular.)  When food was cheap, farmers couldn't make mortgage payments and farms were being consolidated into agro-giants, many (including Pollan) criticized a system in which it didn't pay to farm.  Now, as food prices have increased, we criticize agribusiness for running prices up (see: Mexican tortilla riots), shifting our empathetic focus from the producer to the consumer.

I'm not suggesting that high corn prices are a panacea, nor even that I am smart enough to understand the economics of agriculture.  But it does seem to me that there is a valid point to be made about the impact of food prices on the economics of farming, and that at least within that framework, there are benefits from expensive food.  

It is perhaps an overly semantic point, but one that bears repeating - namely, that low prices are good for buyers, high prices are good for sellers, and there is no price at which nobody wins.

I thought your column last week was excellent--and not overly critical of either Pollan or Waters, although I'm sure they appreciate your attempt this week to emphasize their huge contributions to the sustainable foods movement.

One point I'd add to your original piece: The answer to our current food conundrum you said, "is to make sustainable food more broadly accessible and affordable," with initiatives like Washington state's vegetable snack program.

Another "answer" might be to underscore that industrial food--no matter how cheap--comes loaded with a number of hidden costs. Not only is this in the difficult-to-quantify form of damage to the environment: the phosphate mining, agrichemical pollution, and dead zones you mention. It is also the explicit health costs associated with industrial-style eating: The dollars we may save at the drive-thru window we end up paying (often many times over) at the doctor, when obesity, diabetes, and various other ailments of the overfed set in.

TP wrote:
<<
Pollan here and here; and Waters here, here, here, and here.
>>

How doth the humble Bumblebee
  Bend forth from Flow'r to Flow'r,
And pick the Pollen here and here,
  With no Thought of the Hour!

As well the tender Crocodile
  Pluck'th Fishes without Fear,
From midst the Waters of the Nile,
  Here, here, and here, and here!

Chickens deserve our true friendship! So do fish! So do other sentient beings! Let us learn to be kind.

You're confusing 2 economic effects:  an income effect and a substitution effect.  You're absolutely right that the worsening of the economy and the overall rise in food prices will likely encourage Americans to choose cheaper, lower quality food options.  But there is also a substitution effect.  As the price of industrial food rises, as it will continue to do with rising demand for corn and oil prices, the price of local, organic, sustainably grown food is cheaper by comparison, leading consumers to consume more of it.  To tell which of these effects will be greater, ie whether higher food prices increase the percentage of their diet that Americans get from sustainably grown, local food, we would need to know more about the market.