Want to know whether Inez Tenenbaum or Jim DeMint will win South Carolina’s up-for-grabs U.S. Senate seat?

Don’t waste your time canvassing partisan strongholds like Richland, Lexington, Greenville and Orangeburg counties.

Instead, ask around in Kershaw, Newberry, Saluda and that oldest of S.C. political hotbeds, Charleston County.

Those are some of the state’s 15 swing counties, where the majority of voters have an uncanny ability to pick a winner.

All 15 of those swing counties went for Republican Lindsey Graham in his successful 2002 U.S. Senate race against Democrat Alex Sanders.

Those same 15 counties all voted in larger numbers for Democrat Jim Hodgesover incumbent Republican Gov. David Beasley in 1998.

In 2002, 13 of them went for Republican Mark Sanford instead of Hodges.

An analysis of voting patterns in recent elections shows South Carolina counties can be divided into three categories — 21 “blue” counties that typically vote Democratic, 10 “red” counties that consistently tilt Republican and the 15 swing counties:

• Blue counties generally are more rural and have a much higher percentage of black residents than the state average. Residents also tend to be below the state average educationally and earn less than those in Republican and swing counties.

• Red counties have a disproportionate percentage of white residents, earn above the state’s average income and have larger population centers.

• Swing counties are somewhere in the middle and come closer to mirroring the state as a whole than either red or blue counties.

South Carolina elects its officials by popular vote — not through the complicated Electoral College process that has President Bush and John Kerry obsessing over a handful of swing states.

In the homestretch of the race between DeMint and Tenenbaum, strategists on both sides have put together game plans for one final appeal to voters.

They might choose to shore up their support among traditional Republican or Democratic strongholds. Or they might go after the elusive swing voters who still can be swayed one way or another.

Maybe they’ll do both.

Wyeth Ruthven, communications director for the S.C. Democratic Party, said voting patterns among individuals are more important than how a county leans.

And Luke Byars, executive director of the S.C. Republican Party, said “we feel we need to be everywhere.”

But if history is any guide, odds are that many of the battleground counties — like Kershaw, Newberry and Florence — once again will play a big role in deciding whether Tenenbaum or DeMint represents South Carolina in the U.S. Senate.

Reach Stensland at (803) 771-8358 or jstensland@thestate.com