The Plum Line

As I reported Monday, DeMint and Coburn, two leading conservatives, are calling on fellow Republicans to support letting the subsidies expire as a way to prove that the GOP is serious about reining in government spending. Ethanol subsidies, much like the battle over earmarks, could put GOP senators who have supported them in the past - such as Grassley and Orrin Hatch - in an awkward spot, driving a wedge between them and conservatives who want a harder line on spending.

Grassley responded to our story, firing off an angry tweet at DeMint and Coburn, asking them rhetorically if they're also willing to back the expiration of tax subsidies for the oil and gas industry:

"WashPost reports 2 of my colleagues want sunset ethanol tax credit R they ready sunset tax subsidies oil AND gas enjoys?"

Coburn appears ready to accept Grassley's challenge. His spokesman, John Hart, told me in an e-mail:

"Every aspect of the federal budget should be reviewed. Nothing should be off the table. Congress has to focus on the national interest, not the parochial politics of the past."

With Coburn throwing down the gauntlet and saying not even subsidies for the oil and gas industries should be off the table, it seems there's a clear opening here for an unorthodox alliance between conservatives such as DeMint and Coburn and "green" groups that also condemn such subsidies. It's unclear yet how hard DeMint and Coburn will push this crusade, but Coburn in particular does seem pretty serious.

While the issue could divide Democrats along regional lines as well, it seems more directly relevant to the GOP as a clear test of how serious it is about living up to its anti-spending rhetoric. Senate Democrats may have an opportunity to drive a wedge into the GOP caucus over the issue, though it's unclear whether they have any intention of seizing it.