If you’re itching for the US to cut down on its carbon-puffing and foreign-oil-slurping habits, you’re almost certain to find some relief come January ’09. Not since Nixon signed the EPA into existence in 1970 has the divide between prospective Republicans and Democrats in the White House – at least when it comes to energy and the environment - looked so slim.

That’s mostly because the nigh-on-anointed Republican nominee McCain – while generally true to his market-loving conservative colors – has a distinctive bluish-green hue to his environment platform. McCain’s made a name for himself as the GOP Al Gore and veers from his conservative compadres on issues from gas mileage to tax breaks for big oil.

The candidates aren’t lockstep on all energy issues, though: they split on how much they’re willing to mandate and pay up for their green goals – as well as on how nuclear power and ethanol figure in their energy plans.

But any president is likely to find the real divide - and hurdle to greener pastures – between the Oval Office and Congress, not to mention reality. Conservatives and special interests, particularly in the Senate, very well could continue to throw a wet blanket on some eco-ambitions. The reality of budget constraints and our dependency on foreign fuel (about 30% of all the energy we use), more crucially, means that energy independence isn’t something we should be holding our breath for in the next presidency – or, indeed, in the next generation.

Global Warming

• The diff: Not much – though a Democrat in the Oval Office could spell more aggressive carbon caps – that is, if Congress doesn’t beat the next president to the punch, passing global warming legislation this year.

Ever since Bush (gingerly) threw down the gauntlet on climate change in his ’07 State of the Union Speech, the question of whether to do something about global warming has been replaced by the debate over how aggressively to beat the heat.

The key, of course, to slowing rises in temperature is to slow how much carbon dioxide (and other greenhouse gas) we pump into the air. Both the Democratic candidates and McCain are for “cap & trade” systems, with industry-wide ceilings on carbon emissions slowly ratcheting down over time, and companies given the flexibility to trade part of their emissions (i.e. dirtier factories pay off cleaner factories) – a trick that’s meant to spark innovation and efficiency.

The Democratic candidates would push for a steeper carbon decline: Hillary and Obama want to see us spewing out 80% less by 2050 (from 1990 levels) while McCain puts his target at 35%. That’s a gap worth minding, but chances are cap and trade numbers will be set by Congress with a president having minor nudge influence. (The current frontrunner bill in Congress lands smack dab in the middle, pinning 2050 emissions at 57% below 1990 levels.)

That’s if they get a chance to nudge at all; Congress could steal all the candidates’ global warming glory – by passing a bill before any get into office.

Alternative energy – and Big Oil

• The diff: A Hillary or Obama presidency could spell more cash for alternative energy.

In spirit, all three frontrunners are big on green energy; the question is how much they’re willing to pay for it.

The Dems make no bones – they’d back investment in green R&D (numbers are fuzzy – but somewhere around double the $7 billion-ish that’s spent today) as well as tax breaks for renewables like wind and solar. The tab would be footed by auctions for carbon emissions (as part of the “cap & trade” system mentioned above) and rollbacks on tax breaks for big oil (with extra taxes slapped on for good measure).

The free agent is McCain. While the renegade Republican likes green energy in theory, his campaign doesn’t get specific on practicalities – but it’s hard to see his fiscal-conservative & anti-corporate-welfare instincts not winning out over any will to boost green energy. McCain would be happy take back the oil industry’s tax perks, for sure - but it’s not clear he’d turn around and hand similar perks to renewables.

Congress, again, may make the candidates’ differences moot. This year, the Senate couldn’t edge a bill to pay for green tax cuts past a filibuster. The deal-killer was that alternative energy tax cuts would be paid for by oil tax-hikes (or rollbacks on tax perks – take your pick). Without a shift in the Senate next year – and while Dems’ arms are tied by pay-go rules – the green may just not be around to pay for green.

The candidates could determine different futures for ethanol, though – with Dems as died-in-the-husk supporters and McCain being a historically anti-subsidy kind of guy. On another “alternative” energy front – anti-nuke folks should rest assured that McCain’s plans to back up nuclear power plant constructionare a congressional non-starter.

Odds & Ends

Arctic National Wildlife Refuge: No one’s drilling. Gas mileage: Everyone’s for higher standards, though McCain doesn’t get specific. Waste: No one’s really touching. Nuclear waste: Also low priority. Coal to liquid: All drinking it (as long as it cleans up).