Yesterday, Koch Industries contributed $50,000 to the campaign against I-732, a state ballot initiative which on November 8th could become the first carbon tax in the United States ever. Other contributors include American Fuel and Petrochemical Manufacturers, Western Petroleum Marketers Association, and Nucor Steel.

As we’ve reported previously, I-732 is a weird sort of bipartisan political football. Polluters oppose it, naturally, because they don’t want to go out of business. But some moderate Republicans, including former state Attorney General Rob McKenna, have come out in favor of it because it’s revenue neutral—that is, it taxes carbon emissions while commensurately reducing other taxes including sales tax and a business tax. The left is similarly divided between moderates who embrace the tax as a step in the right direction and radicals who oppose it because it doesn’t go far enough fast enough. (Seattle Weekly endorsed I-732, and we’ve got a comics explainer.)

The vote on I-732 is likely to be close. According to a poll last month by Elway Research, between August and December support for the tax rose from 34 percent to 40 percent, while opposition fell from 37 percent to 32 percent. While that’s cause for optimism on the pro-carbon tax side, 28 percent of respondents were still undecided—more than enough to decide the election.