GETTYSBURG, United States (AFP) - Confederate flags are a hot-button issue in the United States almost a century and a half after the end of the American Civil War.

Case in point: to celebrate this coming week's 150th anniversary of the Battle of Gettysburg, Virginia asked Minnesota to loan it such a flag seized during that turning point in the war, which concluded in 1865.

But Minnesota said no - and a squabble over the symbol ensued between the two states.

Returning the flag would be a "sacrilege" said Minnesota Governor Mark Dayton in response to the request from his counterpart in the former southern secessionist state, Governor Bob McDonnell.

"It was taken in a battle at the cost of the blood of all these Minnesotans," Mr Dayton was quoted as saying by the National Journal on Friday.

"It was something that was earned through the incredible courage and valour of men who gave their lives and risked their lives to obtain it." The flag, in the hands of the Minnesota Historical Society, is just one of several Confederate symbols still seen as a sore spot today.

For example, the writer Jamie Malanowski thinks it's ridiculous that ten US military bases are named after Confederate generals.

"The thought that today we ask any American soldier to serve at a base named for someone who killed United States Army troops is beyond absurd," he said.

The bases include Fort Hood in Texas, which is named after General John Bell Hood who lost the use of an arm at the Battle of Gettysburg, which was fought July 1 to July 3, 1863 and delivered a fatal blow to the Confederates.

Others find offence in the fact that statues of Confederate heroes in southern states face north in defiance of federal power, said William Connery, an expert in Confederate history.

"In some places, there are people who want to get them moved, because the South lost the war and supported slavery," he said.

In Memphis, Tennessee, the city counsel caused a stir in February with its effort to rename several parks bearing the name of southern soldiers, including that of Nathan Bedford Forrest, known for his alleged links with the white supremacist movement Ku Klux Klan.

Peter Carmichael, director of the Civil War Institute in Gettysburg, said there was much flag waving with "not much substance behind it."

"Southern symbols have come under attack in a way that didn't happen 10 years ago," he said.

Many people whose ancestors fought (in) the Civil War feel besieged" and say "the Civil War cause has nothing to do with slavery." "They say it is a war between the big government and small governments," he added.

At a massive re-enactment of the Battle of Gettysburg, the deadliest ever on US soil with nearly 8,000 dead and tens of thousands injured, flying the Confederate flag is not contested.

"It's a heritage," said Mr Chuck Faust, one of about 200,000 history buffs expected to descend on this corner of Pennsylvania over the next 10 days to relive what happened here.

"Slavery was not the issue," said the 52-year-old dressed up as a Union horseman and donning a blue cap. "State rights were the initial issue."

Still, "a vast majority recognise that the Civil War was about slavery and wage labour," Mr Carmichael said.

Historian Allen Guelzo said there will always be individuals who defend the Confederate flag.

"But American Southern society has changed very much," he added.

When the Confederate flag makes its way onto T-shirts worn by youngsters, it is a "symbol of rebellion," he added.

Historian Brain Jordan, for one, noted that the presence of Confederate flags was more pronounced in Gettysburg than in the South.

Mr Malanowski, meanwhile, said one should not boil down Southern culture and heritage to the "outdated, retrograde, racist, separatist and defeated" Confederacy.

Or, for that matter, the Tea Party - an ultra conservative US political movement.

"American culture is so strongly a Southern culture," he added, pointing to jazz great Louis Armstrong and even barbecues.