Virginia Governor Bob McDonnell apologized Wednesday for neglecting to include a mention of slavery in a proclamation proclaiming April "Confederate History Month." President Barack Obama called that "an unacceptable omission" Thursday.

"I'm a big history buff. And I think that understanding the history of the Confederacy and understanding the history of the Civil War is something that every American and every young American should, should be a part of," Obama told ABC's George Stephanopoulos.

"I don't think you can understand the Confederacy and the Civil War unless you understand slavery," he said.

Obama noted that the Virginia Governor had acknowledged that the omission was "unacceptable."

"I think it's just a reminder that when we talk about issues like slavery that are so fraught with pain and emotion, that, you know, we, we'd better do so thinking through how this is going to affect a lot of people. And -- and their sense of whether they're part of a commonwealth or part of a -- of -- of our broader society," said Obama.

As RAW STORY's Dan Tencer notes, "Virginia's own secession ordinance asserted that the state was leaving the Union because the federal government had 'perverted' its powers 'not only to the injury of the people of Virginia, but to the oppression of the Southern slaveholding States.'"

This video is from ABC's Good Morning America, broadcast April 9, 2010.

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