SO NOW the House is going along with Gov. Mark Sanford’s plan to put an arbitrary cap on government spending, right?

Well, not exactly. Mr. Sanford’s cap, complete with its tax rebates, is actually closer to education advocate Tom Truitt’s idea of spending new state revenue building and repairing schools in poor districts than to the Ways and Means Committee budget.

To see why, you have to understand more than the campaign commercial version of the cap.

Early on, Mr. Sanford’s cap was all about getting what he considered a bloated government in check; and his spokesman still talks that way. Never mind that any objective analysis shows South Carolinians spend much less of our money in state and local taxes than people in most states. If government is bad, it doesn’t matter how small it is; it must be smaller.

But lately, the governor is giving an actual reason to limit spending increases. “Leave aside any philosophy” and look at things “from the standpoint of sustainability,” Mr. Sanford told me recently. “There’s a regular peak and valley” in the economy, and thus in tax revenues.

Yet when revenue increases, the Legislature rushes to create new programs, assuming revenue will continue to grow rapidly. “We know these increases are not sustainable,” the governor said.

Well, of course they’re not. And of course a spending cap would curtail the boom-and-bust cycles like the one we just spent the past decade in; so would shutting down government entirely. What makes the cap idea borderline reasonable is a highly technical but essential detail that few people seem to be picking up on: Mr. Sanford doesn’t actually propose to limit spending; he proposes to limit recurring spending.

His plan to send out money above the cap as rebate checks was “just simply about creating a constituency for holding the line,” he told me. “You could hold it all for next year and put it all into highway funds” instead, he said.

Or any other one-time expense. Say, school buses. Or deferred maintenance on state buildings. Or new school buildings in poor districts that can’t afford to replace them. Fact is, our infrastructure backlog is so thick that we could use every penny in revenue growth for years to come and barely make a dent in it.

This is what Mr. Sanford’s plan has in common with Mr. Truitt’s.

Where it differs from Ways and Means is in the committee’s plan to use money above the cap to make up the shortfall in the House tax swap plan. Unlike the governor’s rebate or the school building plan, that’s a recurring expense: It must be funded every year.

Worse, the House’s desire to look like it’s abiding by the governor’s cap could lead to an even more unstable situation. The House plan keeps new recurring spending under a cap by using one-time money to pay for recurring programs.

So what to do?

The House’s approach sets us up for future crisis cuts.

And the governor uses overkill to eliminate boom-and-bust spending because his real goal is to prevent the state from providing any more services than it already does.

That, it must be said, is an awful idea, because the state clearly is not doing everything we need to do: We’re not providing an adequate education for all our kids. We don’t have enough troopers on the roads or guards in the prisons. We aren’t providing adequate care for the mentally and physically disabled people who can’t afford that care themselves. (Perhaps we could do all that if we’d stop doing all the things we don’t need to do, or start doing the things we must do more efficiently. But the Legislature is not going to let us find out, so that is a moot point.)

What to do is reject the governor’s real goal, reject the House’s shell game and modify the cap so it actually addresses the real problem Mr. Sanford claims he wants to address.

One problem with spending caps is that they make it impossible to make a big new EIA-style investment, by essentially prohibiting tax increases. Oh, the Legislature could raise the sales tax, as it did with EIA, or the cigarette tax or any other tax. But it could only spend the money on one-time purchases. We could buy schools but no new teachers, prisons but no more guards, buses but no drivers.

So if you want to turn the cap into a fiscal responsibility tool — which is something we clearly lack in this state — you would add a bypass: Create all the new programs you want — as long as you raise taxes to create a stable, recurring revenue source to pay for that new spending.

There’s little chance the Legislature will raise taxes, but that makes it all the more ridiculous that lawmakers would feel the need to lock out the possibility.

Assuming you really wanted to promote stable, responsible budgeting, the remaining detail to work out is how to calculate a cap.

Mr. Sanford suggests inflation plus population growth, which serves his goal but is overkill for the actual problem. A better idea is to tie spending to revenue growth in recent years.

Obviously, the resulting “cap” wouldn’t suit Mr. Sanford or others who think like him; the Legislature and others probably won’t like it either, because they want to spend new revenue on new programs, even if it’s one-time money.

But smart public policy usually gives all sides some of what they want. That’s intolerable to those on the extremes, but it works well for most of the rest of us.

Ms. Scoppe can be reached at cscoppe@thestate.com or at (803) 771-8571.