Although I'm not committing to be in favor of said magic wand, or any agricultural subsidy for that matter, a few things in this post offer more hope than you afford.

Corn production does not have to be as damaging as it currently is.  Given, square-miles of monocultres of any sort present an ecological threat, but the current practices could be reformed incrementally to greatly reduce their impact.  And when the crops are to processed into fuel, there is the possibility that polycultures could be developed that would be more productive, less harmful, and yeild as much energy as corn alone.  Processing would, of course, be a challenge here.

The corn oil byproduct could also be used as fuel for transportation.

Put aside for a moment the dubious merits of corn as a primary source of ethanol -- perhaps it's true that once production gets ramped up, other crops will get rotated in and some of the damage could be reduced.

But if present farm subsidies were simply dumped into the auto fuels market, how would that not massively distort that market (as badly as the ag market is now distorted)?

And what chance would we ever have of reducing personal transportation in general if "America's farmers" were depending on us to burn their products?

www.grist.org

Even with large ethanol from corn subsidies, 1 dollar per gallon is the figure now, maybe green competition to agribizz monoculture/chemical switchgrass or corn could fool these sneaky lobbyists and their government henchmen.

A solar and wind powered algae based biofuel system can produce a lot more fuel and actually recycle waste and reduce CO2 from power plants doing it.  Will these projects get the 1 dollar per gallon subsidy?

If not, why not?  And shouldn't biodiesel from waste or algae get that same subsidy?

Level the playing field and agri-bizz might be beaten in the market place with  ultra low cost biofuel production from waste using solar and wind power.  With clean water and green electric power as  byproducts.

http://amazngdrx.blogharbor.com/blog

Iogen and Shell are working on building the first cellulosic refinery. They might have all the financing worked out this year. And a DuPont backed group is also working on building a plant. These will be critical in proving the ability of the technology to scale up.

Fusion folks are still trying to figure out how to produce energy for longer than a tiny fraction of a second.

But I still have my bicycles ;-)

(You guys who ride in snow already trump me.)

The studded bicycle tires work great odo, but then there's slush and cars sliding all over.

Cellulosic ethanol, not so great.  Conservation lands put into monocrop switchgrass that needs oil based chemical fertilizer, herbicides, and farming energy  is not a good solution to transportation energy problems.

Furthermore the processing energy will come from fossil or nuclear power.

And as Lester Brown points out water is the big problem with energy farming, it is the limiting factor.  When fuel crops raise the price of food because of water shortage it will be too late, society will already be dependent on fuel farming.

When burned ethanol is only slightly cleaner than gasoline, still producing plenty of greenhouse gases.

Isn't global climate change most of the problem we now have?  Imported energy that entails constant war is a close second, but the main problem must be solved along with the secondary problem.  Switchgrass won't do that, and it drains precious capital from the real effort.

http://amazngdrx.blogharbor.com/blog

I'm baffled by the number of references I've seen lately, in this thread and others, to the increase in nitrous oxide emissions caused by biodiesel (relative to petrodiesel and especially to gasoline).  Has no one heard of a catalytic converter?