Dec. 20, 2010 -- It's been 150 years since South Carolina became the first state to secede from the Union ahead of Civil War, and today the legacy of that watershed moment in American history remains a flashpoint for debate.
Organizers say the "Secession Gala" in Charleston tonight will commemorate the event as a show of courage in the face of encroachment by the federal government on states' rights. But some historians and civil rights groups are protesting the event as the glorification of a defense of slavery.
Dozens of Civil War buffs and Confederate reenactors are expected to attend the $100-a-head event, where they will sip mint juleps, nibble on Carolina crab dip and mingle to the tune of "Dixie" in the presence of the state's original Ordinance of Secession, signed in 1860.
Some participants will reenact scenes from the secession convention, according to the program posted on the event website.
"We are commemorating the lives of 170 men of South Carolina in the same fashion that today we celebrate the 56 signers of the Declaration of Independence -- that was a secession document from the crown of Great Britain," said Mark Simpson, South Carolina division commander of Sons of Confederate Veterans, a group sponsoring the gala.
"These 170 signers in South Carolina, at the risk of their lives said, 'We are doing what we believe we must do to determine our future.'"
Simpson said the spirit of his Confederate forefathers deserves recognition and is still evident in southern politics and culture today.
"The Tea Party movement does seem to indicate people looking to uphold the constitutional rights of states," he said. "In the past year there have been a couple of dozen individual states that have passed sovereignty resolutions, including South Carolina, in response to the health care bill, saying it was unconstitutional to force a mandate upon us."
But during the lead up to the Civil War, historians argue, states' rights meant the ability to preserve the institution of slavery from federal government attempts to bring it to an end. And some say any attempt to separate the issue of state autonomy from the specter of slavery is historical revisionism.
"Slavery was the principal cause of the Civil War, period," said Bob Sutton, chief historian for the National Park Service. "Yes, politics was important. Yes, economics were important. Yes, social issues were important. But when you get to the core of why all these things were important, it was slavery."
The South Carolina chapter of the NAACP plans to hold a silent protest and vigil outside tonight's gala.
"This isn't the type of thing we should teach our young people to celebrate. Commemorate, ok. But to throw a big party, sip juleps, play 'Dixie,' and wear costumes is downright wrong," said Lonnie Randolph, president of the South Carolina chapter of the NAACP. "'States' rights' are cold words used to hide the truth. They were fighting for states' rights to buy, sell, rape and kill African-American slaves. Let's stop using code words."
The commemoration of South Carolina's secession kicks off a year of special events, from battle reenactments to installation of new historical monuments, in dozens of states marking the 150th anniversary of the Civil War.
The state of South Carolina marked Monday's anniversary by unveiling a new historical marker in downtown Charleston at the site where delegates signed the original Ordinance of Secession.
"For many southerners, the Confederacy is not richly understood, but its seen as a movement resisting outside forces. These people are passionate about their heritage," said Mark Tompkins, a political historian at the University of South Carolina. "Still, it's a murky line to commemorate that heritage while condemning slavery."
Earlier this spring, Mississippi Gov. Haley Barbour and Virginia Gov. Bob McDonnell both sparked public outcry after declaring April "Confederate History Month" but failing to make any mention of slavery in the official proclamations.
McDonnell later apologized for what he called a "major omission" and revised the proclamation to include acknowledgment that "slavery led to this war and was an evil and inhumane practice that deprived people of their God-given inalienable rights."
Critics of the secession gala believe a similar qualification for the celebration should be made.
"Was slavery an issue? Of course it was," said Simpson. "We don't deny that. Slavery was a terrible abomination. But this moment 150 years ago was a remarkable period in history and Americans should study and celebrate it."
The Associated Press contributed to this report.