McCainYou could make a pretty simple argument that the fate of the world rests with the United States Senate Republicans:

1. It takes 60 votes to pass a climate bill in the U.S. Senate (assuming it won’t be done through budget reconciliation). Getting the votes of all 58 Democrats and two Independents will be just plain tough, as they might say in the Blue Dog states.

2. It takes 67 Senate votes to ratify an international climate treaty. That requires Republican votes.

3. The international community isn’t likely to pass a climate treaty without the cooperation of the United States.

4. The world needs the Senate Republicans.

The hope is that enough of the most (relatively) independent-minded ones can be peeled away from the obstructionist line and cajoled into supporting a first-step climate bill. That’s why it’s problematic that John McCain (R-Arizona) is acting like anything but a maverick on the issue.

There’s been some interesting reporting on the McCain front today.

Before his most recent presidential run, McCain had long been a leader on taking climate change seriously and doing something about it. He and Joe Lieberman authored the first major climate bill in the Senate in 2003 and introduced new versions in 2005 and 2007. 

POLITICO summarizes his about-face:

Now the Arizona Republican is more likely to repeat GOP talking points on cap and trade than to help usher the bill through the thorny politics of the Senate.

McCain refers to the bill as “cap and tax,” calls the climate legislation that passed the House in June “a 1,400-page monstrosity” and dismisses a cap-and-trade proposal included in the White House budget as “a government slush fund.”

The shift even has former McCain aids “mystified.” Sen. Lindsey Graham (S.C.), the only Senate Republican who’s shown real interest this fall in working with Democrats to craft a climate bill, tells POLITICO, “I wouldn’t be here on this issue without him … He’s the guy that introduced me to the climate problem.”

More bad news: McCain is vulnerable to a primary challenge from the right, according to a new Rasmussen poll. Matt Yglesias concludes:

This seems like pretty much terrible news for the world. The most likely path between Point A and Senate passage of a reasonable climate bill is for McCain to rediscover his interest in the issue. But that’s not the sort of thing a Senator worried about a right-wing primary challenge is likely to do.

For more on the way it used to be: Grist’s interview and overview of McCain’s environmental record from last year’s campaign show how he’s changed his position on a climate plan.

And don’t expect the Republican dynamic to change soon, according to Greenwire. Reporter Alex Kaplun takes a look at upcoming primaries and finds candidates courting the Republican base by taking hard-line positions against a climate bill. His sources say “the general trajectory of the Republican Party as whole for the foreseeable future will be toward opposition of the climate bill.”

All this still amounts to reading tea leaves on where McCain will be if the Senate ever gets around to voting on a climate bill. Maybe he’s still working through some post-election blues. Maybe, over time, he’ll be drawn to playing a constructive role again.