A pitcher is only as good as his legs. A chain is only as strong as its weakest link. And a piece of legislation is only as meaningful as its smallest loophole.

So it’s especially important that House Speaker Pro Tem Jay Lucas, R-Hartsville, makes dead sure that his bill to eliminate shady ways to make campaign contributions in South Carolina is air-tight.

The problems he is trying to address are significant ones. Both Gov. Nikki Haley’s panel on ethics reform and a similar panel of House Republicans have recommended abolishing leadership PACs in an effort to curb the problem.

But the bill’s wording might not accomplish what Mr. Lucas intends. Cathy Hazelwood, a lawyer for the state Ethics Commission, said some of those campaign donations would still remain legal.

In South Carolina, people refer to organizations like the Palmetto Leadership Council, affiliated with House Speaker Bobby Harrell, R-Charleston, as “leadership PACs.” They can make campaign contributions up to $3,500, whereas legislators are limited to $1,000 apiece from other donors. It’s a troubling loophole.

Those at the helm of such PACs earn loyalty from legislators when they send contributions their way. People justifiably fear that these donations are being used to manipulate legislators who should be acting purely in the best interest of the public.

Attorney General Alan Wilson, after agreeing to ask SLED to investigate ethics complaints about Mr. Harrell and the Palmetto Leadership Council, announced Tuesday that he would return $7,000 in contributions he received from Harrell and the group associated with him. He said he will do so in an effort to avoid even the appearance of a conflict.

Rep. Lucas’ intention is just right: “to stop individuals in the General Assembly from forming or having an involvement with political action committees that raise money.”

But Ms. Hazelwood’s perspective should not be ignored. She says that there are two ways candidates get campaign gifts — through leadership PACs and through non-candidate committees (which are very often confused with leadership PACs). Neither vehicle should be allowed to process those donations.

Mr. Lucas told our reporter that he planned to talk with Ms. Hazelwood. We hope he will talk with as many experts as it takes to write an air-tight bill. Otherwise, politicians and lobbyists will find ways to circumvent the law’s intent, and South Carolina’s ethics problems will continue.

Mr. Harrell is a co-sponsor of the bill, noting that it matches a recommendation by the House ethics study committee. We hope he will maintain his support when the bill’s wording is amended and the Palmetto Leadership Council is also restricted.

Lawmakers are finally sounding serious about ethics reform.

They should assure the public that the measures they take to clean up state government will actually do that.