Bio-ethenol: Worth it?

This article seems to provide a good (not-decisive) analysis of whether ethanol is worth it as a fuel.

Bush to back bioethanol - but benefits are in the balance

• 18:37 06 March 2007
• NewScientist.com news service
• Catherine Brahic
• http://environment.newscientist.com/article.ns?id=dn11325&feedId=online-news_rss20

The beginning of a new international trading platform for bioethanol is expected to be announced on Friday, when US president George W Bush meets with Brazilian president Luiz Inacio "Lula" da Silva .

...

Likewise, Tiffany Groode, a graduate student at the Massachusetts Institute of Technology in the US recently showed that biofuel and gasoline production have a very similar footprint, with a slight advantage for gasoline. Groode notes that the difference between the two is so slim that it would only take a few small changes for bioethanol producers to gain the advantage.

So, looks like the US is moving towards ethanol. If there's no environmental gain by doing this, than why? Is it that it just seems more environmental? Is it meant to become just an agriculture-subsidy like Harper's 5% ethanol requirement (CTV.ca News Staff) (it being a subsidy is a theory of mine, no source)? Is it to reduce dependence on foreign oil (don't they import a huge percentage of oil from us now though?)? Is production cheaper than importing oil? Is production steadier?

So, why do this?

References

1. CTV.ca News Staff, Updated Tue. May. 23 2006 11:30 PM ET, Provinces on board with Tory ethanol initiative
   http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20060523/kyoto_provinces_060523?s_name=&no_ads=