There are 2.8 million registered voters in the state of South Carolina, and in the November 2010 general election more than half of them showed up to vote. And while voter turnout in primary elections is historically lower, roughly a quarter of registered Palmetto State voters cast ballots in the June 2010 primary races.

Those are considered normal numbers …

So … how many people showed up to vote in Tuesday’s Republican and Democratic primary elections? At first count, just 278,567 people – or 9.88 percent of the registered voting population.

“Very low,” said S.C. Election Commission (SCEC) director Marci Andino of the turnout.

Really? Try abysmally low. In fact we could be looking at record-breaking voter apathy – although we won’t know that for sure until the SCEC finishes its tabulations.

(To read our live-blog from election night, click here. To view election results, click here).

What caused this depressingly low turnout?

Several things …

First and foremost, there was widespread confusion among the electorate. In addition to numerous candidates being removed from the ballot for failing to file required income disclosure forms, this was the first statewide primary held after lawmakers redrew district lines in accordance with 2010 Census results.

Voters simply didn’t bother to find out who was running … or which races they were supposed to vote in.

Second, the “Tea Party” movement – which catapulted Nikki Haley to the governor’s office in 2010 – is clearly reeling from the feeling. Not only did Tea Partiers in the Palmetto State fail to recruit challengers (viable or otherwise) to run against potentially vulnerable incumbents, but they failed to show up and support the few fiscal conservatives who did file against establishment Republicans.

That’s disillusionment on a massive scale.

Third, this was the first primary since 2000 that did not feature a statewide race at the top of the ticket. In 2002, 2006 and 2010 statewide constitutional offices were on the ballot, while in 2002, 2004, 2008 and 2010 there were contested U.S. Senate primaries. The lack of a “big ticket” race also played a role in driving down interest – and turnout.

Despite all these factors, voter participation was still shockingly low. Most analysts we spoke with said they expected roughly 15-20 percent of the electorate to show up and vote on Tuesday – predictions which were obviously far too optimistic.

“Decisions are made by those who show up,” Harry S. Truman once said.

Or was that Woody Allen? Or Aaron Sorkin?

We forget … but nine out of ten registered voters in the Palmetto State didn’t bother to show up in this election. That’s sad … but what’s even sadder is that it’s hard to blame them for abstaining.