John Edwards’ bid for union support seems to finally be paying off for him — yesterday, his campaign won the support of the steelworkers and mine workers unions. Which raises an important question: To what extent is Edwards’ support for mine workers (and their support for him) incompatible with his climate-change platform? Edwards was the first of the Democratic hopefuls to put forth an ambitious climate-change plan (perhaps inspiring slightly more ambitious offerings from Chris Dodd and Bill Richardson), and he remains the only one of the three leading contenders to have made addressing climate change a priority — we’ve heard standard platitudes from Hillary Clinton, and a series of confused and incrementalist proposals from Barack Obama.

So I asked the Edwards campaign if supporting coal miners is at odds with supporting the human race (of which coal is an enemy, as we at Grist are fond of reiterating). They sent me the following statement:

John Edwards is gratified by the support he has received by mineworkers, who have helped give him the largest bloc of union support — combined, more than 1.8 million members and retirees — among any of the presidential candidates so far.

John Edwards remains committed to his ambitious goal of ending global warming by reducing greenhouse gas pollution by 80 percent by 2050. The reality is that coal is going to be an important source of American energy for decades to come, and we need to find a way to use it without heating the planet. He has called for a moratorium on new coal plants unless they are compatible with efforts to capture and permanently store their emissions underground. He has also proposed a historic, $1 billion a year effort to develop and implement feasible technology to do this as quickly as possible.

This is, I suppose, significantly better than Obama’s plan to subsidize both sequestration and liquid coal research and Clinton’s generally coal-friendly history in the Senate. But it’s also a fascinating move by the miners themselves. It’s possible to read this any number of ways. Perhaps they’ve accepted the fact that coal is a dangerous old dinosaur, and have thrown in their lot with the most generally labor-friendly of the front-runners (unlikely). Or perhaps they believe their industry has become so indissoluble from the American political system that even the most environmentally friendly politician in the top tier won’t be able to change things. If that’s the case, then it makes sense for them to posture a bit (more likely). Whatever the case, it’s worth noting that a union comprised largely of mine workers has endorsed a candidate who’s called for a moratorium on the construction of new coal plants.