Sigh. On the plus side, the only Republican votes for this were from the Greater Corn Belt, if you include Mississippi, which since the advent of the Great Ethanol Subsidy, has been increasingly shifting from cotton cultivation to growing corn for ethanol. Although Arkansas should technically be making the same move as Mississippi, and yet both senators, the Democratic Pryor *and* the new Republican Boozman, voted for the Coburn amendment. Kentucky's a minor member of the corn belt as well, and yet both of Kentucky's Republican senators piled into the "yes" column; if Rand Paul had voted against this, he probably would have been eaten alive by his supporters. The Maine Sisters, the Alabama Porkbarrellers, the Republican West - they all went anti-ethanol. Hell, even Brown kept to the straight and narrow.
So, in short, what we have here is a *corn belt* Republican problem, not a whole-party problem.
Update: apparently this was the fruit of Grover Norquist's demented anti-genius. He's so petrified of the spectre of anything anyone could possibly characterize as a "tax increase" that he's stomping about, defending distortive corporate-welfare abominations like the ethanol "tax credit". Norquist's Americans for Tax Reform is an abscess on the conservative movement, a corruption. The best construction to place upon his organization's activities is that they've slid from pro-capitalist tax reform to pro-big-business tax-credit farming. A more likely construction is that he was always in this for the lobbying opportunities, and that his little cottage industry is built upon lobbying and rent-seeking under the color of "tax reform".
Anyways, his obnoxious insistence on characterizing the elimination of subsidies as "tax increases" gave most of the corn-belt Republicans enough cover to do the locally expedient thing instead of the principled thing. Damn him, anyways.