Those karate-chop TV ads castigating South Carolina's senior U.S. senator for heresy on Social Security, we'd wager, won't cause him much damage. South Carolinians are pragmatic people, and Sen. Lindsey Graham, R-Seneca, is a pragmatic politician. Like most of us, he understands that Congress can't begin to talk about adding private investment accounts to the national old-age insurance system until it repairs the actuarial defects that threaten to bring the system to its knees.

The Club for Growth is running attack ads against Graham on S.C. TV stations because he's willing to consider an idea that originated with the Democrats. He recently said increasing payroll-tax collections by raising the personal income limit subject to the Social Security payroll tax from $90,000 to $150,000 could be a useful idea.

The Club wants South Carolinians to remind him that this is an outrageous deviation from conservative orthodoxy. Club leaders underestimate our intelligence. South Carolinians understand that Congress, for more than 20 years, has spent the excess payroll tax money in the Social Security "trust fund" for other federal purposes. Payback time is virtually upon us.

In 2008, older baby boomers will begin to retire, with a fresh wave hitting the system each successive year. By about 2012, Social Security won't collect enough payroll-tax revenue to pay claims. At that point Congress will have to begin repaying the money it annually has borrowed from the system (except for a few years in the late 1990s). Senators and representatives will have three painful alternatives for meeting that obligation: allowing deficits to soar to even higher levels, slashing federal programs and/or raising taxes. Failure to take such actions in some combination would force Social Security, in time, to pay partial benefits to retirees. The system doesn't have the option of going into debt to meet its obligations.

You don't have to have a Ph.D. in finance to figure out that the least painful way to forestall such national misery is diverting more money into the system near-term - as raising the income limit on payroll taxes would do. What we have here is a manifestation of the famous Fram oil-filter analogy: We can pay a little more now to keep the Social Security engine running smoothly, or we can pay a bundle later to overhaul it after it starts belching smoke.

The Club is right: Raising the payroll tax income limit would amount to a tax increase, and that stinks. But blame this situation on the Democratic and Republican Congresses that for a generation have treated the Social Security "trust fund" as a slush fund to mask their spending excesses. At times such as this, ideological purity must go out the window.

Neither the Club for Growth nor anyone else who says Social Security can be repaired without more revenue is able to explain exactly how this would work. Presumably, Congress would pad deficits ad infinitum to pay the freight while shutting down entire federal agencies to stretch tax collections farther.

Meanwhile, presumably, the introduction of private investment accounts would transform Social Security into a kind of federal 401K, undermining its roots as a generational-transfer entitlement. Most Americans appear to be unwilling to allow such a radical reform. For his willingness to craft a fix that Americans would accept, Graham is getting some heat. But it's hard to imagine that South Carolinians would punish him for doing what most of them want him to do.