South Carolina cannot afford the income tax cut being pushed by Gov. Mark Sanford with support from legislative leaders.

Sanford campaigned on it and insists that the public expects him to deliver.

His best point is that many small businesses use the personal income tax forms, and they should expect to pay the same lower rate available to big business. That discrepancy should be addressed, especially in light of the fact that our biggest business is small business. The backbone of business in this community and the state for the foreseeable future is small business. In theory, if they were not paying a higher income tax, they could help employees with health insurance, or grow their business to increase the dollars flowing through the community.

But the proponents are brushing aside the flip side. They are underplaying the financial impact of the governor's largess. In a luncheon with editorial writers last week, Sanford could not say what he thought the long-term cost of the move would be to the state.

The cost in the current budget proposal would be $6 million. That means the state would have $6 million less to meet its obligations. But that is only the beginning. The cost to the state skyrockets as the tax rate drops from 7 percent to 4.75 percent over the next 10 years. It would go up tenfold next year and double the year after that. In the end, it would cost the state almost $1 billion, or about $960 million per year, according to the state Board of Economic Advisers.

House Ways and Means Committee Chairman Bobby Harrell favors the tax cut, saying it would spur the economy. Yet at the same time, he acknowledges that the state faces a big struggle to meet its obligations to Medicaid and the Education Finance Act for public schools.

Proponents say it will attract wealthy retirees to the state, but they already have been coming by the droves for many years, often citing the low taxes here. State Sen. Scott Richardson, R-Hilton Head Island, who is concerned the state cannot afford the proposal, said that in 10 years serving in the General Assembly, not once has anyone come to him and said, "What we need is a lower income tax rate."

One reason might be that there are so many adjustments on the state tax forms that few people are actually paying the rates the governor thinks are out of kilter with neighboring states.

Sanford hopes the cut will attract entrepreneurs who will start businesses based on intellectual capital. He thinks it will make the state more competitive.

But he also acknowledges that a more comprehensive look at tax reform is unlikely, noting it would be hard to push something comprehensive through the give-and-take of the legislative process.

In that environment, it is crucial for legislators to know the full, long-term cost of the incremental tax reform they are constantly rolling out. They need to discuss honestly with the public what the public will be giving up in return. It may be public safety, public education, environmental protection, health care for the poor -- the list is long -- but it will be something. South Carolina cannot afford it.