In this ad, which is pretty good, John McCain plays up his distance from Bush on the environment:

But over the past few days, McCain keeps circling back into the Bush orbit on the environment. He declared that the “cap” in his cap-and-trade carbon proposal was not mandatory, something that will please the oil, gas and coal industries, and large industry as a whole, because it makes the entire proposal meaningless. This was a little too reminiscent of Bush’s rescinded 2000 promise to regulate CO2 emissions.

Yesterday, he came out for lifting the ban on offshore drilling, and Bush has enthusiastically climbed on board. Obviously: pushing for more oil production is inimical to a policy focused on reducing carbon emissions. It doesn’t matter where you stand on global warming or energy policy – just from the standpoint of coherence this is a bloody mess. As it usually is with McCain, we don’t know if he is playing politics with carbon and trying to reassure Republican big business that things will go on as they always have, or if he is genuinely unaware of the contradiction. Or some muddled version of both. This again points to a basic problem with McCain’s candidacy, which is that we really don’t know which diametrically opposed promises he will choose to honor if elected; he probably doesn’t know himself at this point.