Cap-and-trade is proving to be the vote that wouldn't go away.

Case in point: For the second year in a row, Farmfest's congressional forum was highlighted by Reps. Tim Walz and Collin Peterson's support for the bill – which is incidentally DOA in Congress.

In an interview after the event, Walz said it is "debatable" whether a cap-and-trade system is superior to other methods of clean energy legislation, such as tax credits or imposing a carbon tax.

"That's the debate that I think should be asked on this," Walz said. "I think many of us, Collin included, [are] not altogether comfortable with the cap-and-trade mechanism, but there were so many other things in [the bill] that went the right way."

He was comfortable supporting the legislation, he said, because he knew it would change substantially before it came back for a final vote -- after it had been sent through the Senate and conference committee.

"You've got to start somewhere," Walz said. "I never thought that the final version I would vote on would look anything like it, but it's to move it forward."

Unfortunately, he said, there was no "concerted endgame" on the bill. Hence why he and others are now stuck defending their 2009 votes.

This defense -- that the bill was likely to change -- is similar to what Peterson told radio host Scott Hennen several months ago.