Just now everyone's talking about health care. I want to talk first about concrete.

Concrete is a marvelous substance. There's a reason it is the backbone of modern cities, and some much-loved ancient treasures, like Rome's Pantheon, as well as much-hated eyesores, like Boston's appalling City Hall and North Korea's notorious "Hotel of Doom": It's cheap. It's strong. It's versatile — until it sets. Then you're basically stuck with it.

That very inflexibility is probably one reason that buildings like the Pantheon survived for us to admire them. Other ancient treasures were torn apart by the locals looking for building materials, but concrete buildings could not be repurposed stone by stone.

Faithful readers may see what I'm getting at: Some forms of government policy are built of political concrete. Once done, they cannot be renovated, added to or even destroyed without immense cost; for that reason, they tend to go on much as they always have, for good or for ill.

This was the problem the Democrats faced with Obamacare. Other countries, it was often observed, had a national guarantee of health insurance; surely, we could build a system very much like those. But the other countries had built their systems earlier, when there weren't so many concrete towers already in the way. By the time Obamacare came on the scene, America already had government programs that were propping up health care for almost everyone in the country: tax-subsidized employer-sponsored health insurance, Medicare, Medicaid, the VA. No one was willing to shoulder the cost of knocking those things down and designing a rational, well-built structure to take their place, so instead the administration threw up an annex next to the Medicaid edifice, and tore down the little remaining patch of ground that wasn't government-subsidized, and put up a new tower to hold its residents.

The planning was haphazard, the work shoddily done, and the result kept threatening to collapse.

And yet it was locked in. That whole "political concrete" thing. For the enthusiasts, the very difficulty of alteration was not a bug but a feature, because it meant that it would be hard for Republicans to undo. So we were all left with a subpar system that is difficult to either repair or replace.

That is unfortunate, but it is now a fact, and Republicans, like so many opponents of Brutalist architecture, are going to have to contend with that reality. We cannot simply get rid of what Democrats built, and then perhaps, at some more convenient date, start over with a sounder design. The old structures are gone and will not spring back up of their own accord if we knock down what's there now. All you get from a hasty demolition is a big pile of rubble.

Very expensive rubble, for Republicans, who will have to face angry voters who now have neither their old home nor the new. The base may rejoice when they hear that Obamacare has been "repealed" (sort of). But their cries of glee will be drowned out by their wailing when they find that they cannot buy individual insurance at all.

That's why I don't understand what Republicans are trying to do with this bill. What do they think will happen after they proudly proclaim that they've repealed Obamacare — followed in short order by the complete implosion of the individual market? Do they really imagine that they will be allowed to leave the rubble-filled lot there and proclaim that they've undone President Obama's mistake? Or that, having watched them destroy the individual market, voters will be eager to let Republicans touch any of the other structures cluttering up America's health-care policy landscape?

The idea, as I understand it, is that after they pass this, they will come up with the currently mythical Phase II and Phase III bills, which are somehow supposed to garner Democratic senators' votes (the same votes they can't get now, incidentally, which is why they're pushing forward with a partial bill that can pass with fewer votes through a streamlined budgeting process). But insurers will start to submit their proposed rates for 2018 in a few months. That is likely to become the effective deadline for any further tweaks, because if insurers think the collapse of the individual market is imminent, they will decline to sell into that market, and then the collapse will no longer be a forecast, but a fact. And Republicans will be under immense pressure to fix it immediately — meaning, with a legislative process even hastier, and less-well-thought-out, than either the process of composing this bill, or the year-long saga of drafting Obamacare.

You do not fix a concrete eyesore in stages.

You either knock it down, or you leave it where it is and learn to live with its flaws. If Republicans want to actually do a radical renovation of our nation's health policy architecture, then they should get a reasonable estimate of the costs, grit their teeth, and go ahead and actually build something sound, and enduring, while demolishing substantial portions of the ugly and unsustainable mess we currently have.

If Republicans cannot get up the will to bear those costs, then they should do nothing, and start preparing their rebuilding strategy while they wait for the flaws in Obamacare's structure to bring down the individual market on its own. Neither strategy is painless, because the ossified mistakes of earlier policy-making have taken all the cheap and attractive options off the table.

But either is better — for America, and for the Republican Party — than setting new mistakes in stone.