Cross-posted from Daily Kos and Congress Matters.
Tom Harkin is one of the more liberal Democrats in the Senate. Up until very recently, he was in a powerful position to affect the Senate version of ACES, as chairman of the Agriculture committee, but that role is now held by Blanche Lincoln (D-Walmart). Healthcare's gain is ACES's loss. However, Harkin is still a member of the committee, and hopefully wields some influence. (See [http://www.tnr.com/blog/the-vine/blanche-lincoln-ag-chair-say-it-aint-so this] for the chairmanship changeover.)
Harkin was in a position to keep Collin Peterson's additions to the bill (remember the House Ag guy who held the bill up for more breaks for farmers?). He *is* a farm state Senator, supporting farm interests, including a strong emphasis on biofuels from corn and soy. However, he has a history of strongly supporting renewable energy, efforts to reduce greenhouse gas emissions, and the use of biochar to sequester carbon.