Prying answers out of the candidates about science-related issues this electoral season has proven almost as challenging as prying interviews out of Sarah Palin, McCain’s elusive running mate. Aside from an early focus on the candidates’ respective energy policies (see: their positions on offshore drilling), the press has shown relatively little interest in scrutinizing Obama’s and McCain’s views on matters of science.

Even the once controversial issue of stem cell biology, which, alongside gay marriage, helped mobilize the conservative base for George W. Bush during the 2004 election, has received little shrift this time around.

Fortunately, a small team of motivated individuals, led by Shawn Lawrence Otto, Matthew Chapman and DeSmogBlog contributor Chris Mooney, took it upon themselves to coax science back into the political debate by founding Science Debate 2008. Their mission: to foster a debate between the presidential candidates about the most important science issues of the day. It has been almost a year since the group’s inception, but its hard work has finally paid off, with both campaigns agreeing to answer 14 questions about a variety of topics, including climate change, education and genetics.

So how did the candidates fare side by side? In general, both expressed interest in boosting funding for basic and applied research (though a recent Science article seemed to suggest a McCain administration would do otherwise, instituting what would amount to a one-year freeze in research funding), making the case that a robust science and technology infrastructure is essential to stimulate innovation and economic growth. Not surprisingly, Obama is much more willing to give the government a greater role in taking on these issues whereas McCain prefers to let the free market dictate the outcomes.

While both made similar noises about tackling the growing water crisis, improving ocean health and prioritizing scientific integrity, they differed on most other issues – particularly health, stem cell research and, you guessed it, energy and climate policy.

On paper, their plans share a few key similarities: Both want to significantly cut greenhouse gas emissions by mid-century – Obama by 80 percent and McCain by 60 percent below 1990 levels – by instituting a market-based cap-and-trade system, and both want to boost investment in renewable energy technologies. Once you get past the generalities and into the nitty-gritty, however, it’s clear that a McCain presidency would offer a starkly different agenda than an Obama one.

Take their cap-and-trade proposals, for instance: While Obama would require all carbon permits to be allocated through an auction system, McCain would give the lion’s share away and let the market price them. The benefits of Obama’s approach are two-fold: Not only would it ensure that companies pay the full price for the right to pollute, it would also help raise a significant amount of funds that could be plowed into renewable energy projects or returned to taxpayers as regular dividend payments.

Giving away too many credits at once could cause the price of carbon to plummet, as it did in the European Union during the first phase of its emissions trading scheme, resulting in little, if any, emission reductions.

On other policies, McCain’s proposals seem more like gimmicks than anything else. Whereas Obama would invest $150 billion in clean energy research and development over the next decade, McCain would award a $300 million “prize” to whoever develops a battery package that “leapfrogs” existing plug-in hybrid and electric vehicles technologies. Though there’s nothing wrong with rewarding ingenuity, it says something about McCain that he’s willing to make this a central plank of his energy agenda – never mind the sheer difference in dollar amount.

And while McCain likes to talk a good game about funding renewable energy technologies, his Senate record says otherwise. As Joe Romm noted in a recent piece for Salon, McCain’s (abysmal) voting record on supporting clean energy matches that of Oklahoma Senator James Inhofe – hardly the type of politician you’d associate with having a progressive stance on wind, solar or other renewable technologies (or climate change, for that matter).

The single “alternative” energy that McCain has championed throughout his Senate career is none other than nuclear power – a, shall we say, risky technology that doesn’t exactly scream environmental “maverick.” It’s bad enough that McCain’s plan calls for the construction of 45 new reactors at a (whopping) cost of $315 billion; taxpayers would be responsible for shouldering much of the burden – and risk. It’s true that Obama also supports some investment in nuclear power. However, unlike McCain, Obama is hardly a one-trick pony: His plan would invest in a number of renewable energies, advanced vehicle technologies and energy efficiency projects, to name a few.

Oh, and did I mention McCain also really, really likes offshore drilling?

While it’s always risky to take candidates fully at their word – seeing as their future policies would inevitably be constrained by the prevailing political climate – one can’t help but feel especially dubious about McCain’s claims. He has so far displayed a remarkable knack for flip-flopping (or outright lying) about almost every one of his core beliefs – whether it be offshore drilling, the influence of religion in politics or the sanity of Bush’s tax cuts.

Who’s to say he’ll keep his word on aggressively tackling climate change? His pick of Alaskan Governor Sarah Palin, an avowed skeptic of man-made climate change, as his running mate and his decision to back offshore drilling to the hilt have completely undermined his already vacillating environmental bona fides. There’s even some evidence to suggest he’s no longer fully onboard with the concept of a “mandatory” cap-and-trade system .

So, yes, let me be honest and say that I wouldn’t be too surprised if Obama eventually reneged on a few aspects of his ambitious energy and climate package. (Luckily, there’s already a lot to like about it.) When it comes to McCain, though, I’m afraid I can’t even say with complete confidence that he’ll stick to even the basics of his agenda.