I wrote a post back in the midst of the Frankenstorm Sandy that, I think, wasn’t written as clearly as it might have been, and hence one of its major points didn’t come across. It really deserves a much longer discussion, but I’ll try to give at least a clearer outline here.

The climate change debate to date has overwhelmingly revolved around efforts at prevention – what can we do to reduce carbon emissions, how expensive will that effort be, would it be worth it if it worked, and would it even work. That’s an important discussion, but the most optimistic scenarios for reducing emissions still assume that the world is going to be pouring a lot of carbon into the atmosphere for years, even decades to come, and the mainstream climate models assume that we’re already over the limit in terms of atmospheric carbon.

I’m not arguing “it’s too late and therefore we shouldn’t do anything.” Not at all. I’m just saying that if even if we do everything those most alarmed by climate change want done, we’d still be facing the prospect of significant climate change. Which is going to require costly adaptations, particularly to coastal areas, like New York harbor.

The cost for building a seawall to defend New York has been estimated at $17 billion. Triple that on the principle that you always triple contractor estimates – that’s $50 billion. But New York is only one city, and those estimates are for barriers to deal with storms on the level of Sandy and Irene. If sea levels continue to rise, Sandy’s surge won’t look like an outlier for very long. The way we normally do things in this country, we’ll probably see multiple rounds of construction as estimates of the size of likely surges change, which will be less cost-efficient than doing a much larger project designed to handle more alarming scenarios. And then, of course, there’s Miami, and Tampa, and Houston, and Norfolk-Virginia Beach to think about.

Over the next decade, we’re going to be spending hundreds of billions of dollars on protecting our vulnerable coastal cities and infrastructure from the effects of climate change. Or we’re going to be spending hundreds of billions on disaster recovery, and we’ll still need to spend hundreds of billions on climate adaptation because the disasters will keep recurring.

How are we going to pay for this?

I’ve been making the argument in this space for some time that we’re having the wrong spending debate. The debate about whether we should be spending more and borrowing more, or whether we should be spending less and borrowing less, really is secondary. The real problem is that we are unable to debate what our spending priorities ought to be – which is to say, what spending is most important for the future of the country.

Mitt Romney told the country on national television that, as President, he wouldn’t borrow for any program that wasn’t worth being in hock to China for. And yet, the two areas where he promised to increase spending were on reimbursements to health-care providers for current retirees, and on the military.

Climate adaptation is going to require a lot of money. Not impossible amounts of money, but real money – the kind of numbers we threw away on our Iraqi adventure. And we’re going to be spending that money not to improve the productivity of our economy, which would increase our national wealth, but to prevent disasters that will otherwise severely deplete our national wealth. We’ll be spending more just to stay in place, in other words. Which means we can’t just put it on the credit card and not worry about it. We have to think in terms of trade-offs.

Moreover, it’s going to mean taxing people who are less-likely to be affected by rising sea levels and more severe storms, to pay to protect people who are more-likely to be so affected. Which means, if it’s going to happen, we’re going to have to think of ourselves as one country, and not just a collection of squabbling constituencies.

But our political system seems completely incapable of thinking in those terms, and a major reason is that one of our major parties is committed to the proposition that anything it doesn’t like – from climate change to non-white voters – doesn’t exist, and that doesn’t seek power for any purpose but to make sure that power remains in the “right” hands.

Based on the way the GOP has behaved since the mid-1990s, I would expect them to stand squarely against doing anything at all, or, at best, to agree to such spending only if it is never paid for, and if inland constituencies get their own share of wasteful government gravy. In other words, I would expect the GOP at the national level to be an entirely negative force, even in the terms they supposedly care about: the overall fiscal picture of the country.

I’m waiting, on this as on so many other topics, for the Republican Party to prove me wrong. Because I want the country to have two responsible governing parties.