FOR THREE years now, first candidate and now Gov. Mark Sanford has been promoting his income tax cut as a way to spur badly needed economic development in South Carolina.

No doubt it would do that — just as exempting businesses from all taxes or all regulations or all lawsuits would spur economic growth. The question lawmakers need to ask is whether cutting income taxes is the best way, or even a good way, given its cost, of spurring growth.

If they take the conservative approach to government — which demands that you target your solution narrowly to the problem — they will have to conclude that it is not: Cutting the top income tax rate means my taxes will be reduced, but that’s not going to spur me to start my own business — just as it won’t spur the vast majority of South Carolinians who receive the tax break to start their own businesses.

There are far less drastic ways of accomplishing that goal.

As lawmakers take up the income tax reduction plan today, it’s useful to consider some of those more conservative approaches.

Mr. Sanford says cutting the top income tax rate will attract wealthy retirees, entrepreneurs and folks looking to locate corporate headquarters to our state. He says this will work becauseSouth Carolina’s 7 percent income tax rate is the fifth-highest in the nation.

But if you look beyond the rate tables to the effective tax rates — the rates people pay once they’ve factored in all the deductions, credits and exemptions their state offers — ours is in the middle of the pack, even near the bottom under some calculations.

Last week, Mr. Sanford rejected considering those write-offs because “you’re still saying the politician should ultimately pick the winner and loser, which is not something I philosophically believe.”

Whether you agree with offering tax exemptions and credits or not doesn’t change the fact that we do, and that our effective rate is much lower than it looks. But let’s set that aside; I’m not crazy about the way all that works either, because I’m not convinced legislators have made good choices about what to encourage and what to discourage through the tax code. So here’s an idea: Why don’t we get rid of some of those exemptions, deductions and credits, and lower the tax rate?

That way we will bring in just as much money to pay teachers and Highway Patrol troopers and prison guards, the state will be less involved in picking winners and losers, and when outsiders look at state-by-state income tax rates, South Carolina will land in the middle or near the bottom. Call it the truth-in-taxation law.

Mr. Sanford also argues that cutting the top income tax rate would level the playing field for small businesses. Corporations pay a top income tax rate of 5 percent, but since most small businesses file as individuals, they pay a higher rate. This clearly doesn’t make sense, it probably is discouraging business growth, and it does need to be changed.

There are two ways to do that. One is to tack on an extra business exemption that would effectively lower the tax rate small businesses pay, and the House takes up one such effort today. But Mr. Sanford doesn’t like the government picking winners and losers, and there’s a cleaner approach: Let the small businesses that aren’t corporations file corporate income tax rather than personal income tax returns.

The downside to both of these targeted solutions is that they’re a lot more complicated than simply cutting the tax rate: You have to decide which exemptions and credits and deductions to eliminate; you have to set up rules for treating non-corporate businesses as corporations.

But there’s something to be said for requiring a little more thought before you change the tax code, since one of our greatest tax sins in this state is applying simple solutions to complex problems. That’s a routine practice that routinely causes unintended ripple effects on the rest of the tax code, and has resulted over the years in a tax system that is too complex to even evaluate. That’s why the best approach is to revamp the entire tax code all at once.

Of course, these focused fixes won’t satisfy you if your goal is not just to attract growth but to shrink the size of government — which Mr. Sanford talks about constantly, except when he’s promising that cutting the income tax rate won’t result in less money to spend on essential state needs.

Perhaps it’s justifiable for Mr. Sanford to propose cutting state revenue, since he’s apparently more than willing to mothball popular programs that our state could live without, and redirect the savings to essential programs that have been getting short shrift. But the Legislature hasn’t been willing to do that. So if you’re a legislator, going along with the governor’s plan to reduce income tax rates means you’re voting to starve important programs that you, as the public’s representative, have decided our state must provide. And that’s irresponsible.

Particularly when you can accomplish the goal we all share, of growing the economy, without taking such drastic action.

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