There are roughly three million registered voters in South Carolina … but if you think even half of them will show up to cast their ballots on this primary election day, you’re crazy.

In fact if you think even one quarter of them will bother to cast ballots … again, you’re nuts.

Even with a “high-profile” U.S. Senate race on the ballot, political experts are expecting depressed turnout across the Palmetto State this week. How low? Well, the last statewide primary day drew an abysmally low 13.6 percent of the electorate – well below the 2000 turnout threshold of 18.7 percent.

Why do we rewind the clock to 2000? Well, that was the last time a primary election 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 played a role in driving down interest in 2012 – along with the ballot debacle that saw hundreds of candidates removed from the electoral process due to a technicality.

This year should see “higher” turnout given that there’s a contested U.S. Senate race involving a polarizing incumbent – U.S. Sen. Lindsey Graham – but even that race has failed to generate much in the way of drama.

Why not? Because none of Graham’s “Republican” challengers have been able to rally the financial resources or grassroots support necessary to mount a credible challenge to the two-term liberal – meaning the millions of dollars in national “anti-Graham” money has stayed on the sidelines.

As a result, Graham appears poised to win the GOP nomination on the first ballot this week – a truly shocking fact when you consider how vulnerable he should (and could) have been in the so-called “most conservative state in America.”