THE LATEST MCCAIN DISAPPOINTMENT…. With the American Clean Energy and Security (ACES) Act on its way to the Senate, the global warming legislation’s fate remains very much in doubt. Not only are there skeptical centrist Democrats to worry about, but the prospects of winning over Republican votes appear slim.

It’s tempting to think John McCain would be willing to show some leadership on this. It was, after all, just a year ago, after he’d secured the Republican presidential nomination, that the Arizona senator acknowledged the climate crisis and said the United States “needs … a cap-and-trade system.” It was a position he reiterated throughout the year.

As Ryan Powers reports, however, McCain has since decided that a cap-and-trade system is a “far-left” agenda item, which he, like many far-right activists, now prefers to call a “cap-and-tax” system. Here’s McCain yesterday on an Arizona talk-radio show:

“It’s really terrible, because I believe that climate change is real, I believe it is something that we need to address, and I’m sure that a lot of Americans do, but to do so with a bill like this? … What [the Obama administration is] doing is using cap-and-trade…to raise billions of dollars so they can spend money on Cash for Clunkers, you know, buying General Motors and Banks and the world’s largest insurance company…. So it started on the wrong path and now it’s just turned into, you know, it’s laws and sausages at its worst in my view.

Ryan fact-checks McCain’s criticism — not surprisingly, McCain doesn’t know what he’s talking about — but I’d just add that the Republican senator’s bizarre and baseless opposition makes the larger effort that much more difficult.

Keep in mind, while reconciliation rules are in place for health care, center-right Democrats made it so that Republican obstructionism can kill climate-change legislation. To get to 60, the Democratic majority will need some support from those handful of Republicans who take science and global warming seriously.

McCain was supposed to be one of them. That now appears unlikely.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.