7.5 billion gallons would be 179 million barrels.  This is a drop in the bucket.  You can save more just be imposing tighter fuel efficiency standards for cars and SUVs.  
You could also save more by cutting subsidies to oil companies, therefore raising the price and force the market impose tighter fuel standards.
(And save some tax-payer dollars!)
Though the demand levels may encourage supply if states move to make its use mandatory. Also, as Bloomberg points out, the gallons of ethanol and gasoline differ in energy content, so prices are not exactly comparible.
My first thought exactly... and is that 178mb per year? So < 500kbpd. Or is that from now until 2012? Also, does anyone know exactly how many acres it takes to make 1 gallon of ethanol (neglect EROEI). Furthermore, consider that roughly half of U.S. oil usage is for gasoline. Unless anyone has figured out how to make plastic from ethanol, there is still a problem.

The politicians think they can grow enough corn / sugar and build infrastructure to make ~ 14mbpd or ethanol in 3 years?!?!

Sorry that I have to correct but due to lower energy content 7.5 billion gallons of ethanol are equivelent to just 4.6 billion gallons of gasoline or 109 mln.barrels of oil.
This would save 5 days (1.37%) of current USA oil consumption annually which might not be impressive but is not that insignificant. I agree though that with higher CAFE we could save much more.
Thanks for the figures.  I wonder if biodiesel is similarly energetically challanged.