[Sociologist James W. Loewen is the author of"Lies My Teacher Told Me" and co-editor, with Edward Sebesta, of"The Confederate and Neo-Confederate Reader."]

One hundred and fifty years after the Civil War began, we're still fighting it -- or at least fighting over its history. I've polled thousands of high school history teachers and spoken about the war to audiences across the country, and there is little agreement even on why the South seceded. Was it over slavery? States' rights? Tariffs and taxes?

As the nation begins to commemorate the anniversaries of the war's various battles -- from Fort Sumter to Appomattox -- let's first dispense with some of the more prevalent myths about why it all began.

1. The South seceded over states' rights.

Confederate states did claim the right to secede, but no state claimed to be seceding for that right. In fact, Confederates opposed states' rights -- that is, the right of Northern states not to support slavery.

On Dec. 24, 1860, delegates at South Carolina's secession convention adopted a"Declaration of the Immediate Causes Which Induce and Justify the Secession of South Carolina from the Federal Union." It noted"an increasing hostility on the part of the non-slaveholding States to the institution of slavery" and protested that Northern states had failed to"fulfill their constitutional obligations" by interfering with the return of fugitive slaves to bondage. Slavery, not states' rights, birthed the Civil War.

South Carolina was further upset that New York no longer allowed"slavery transit." In the past, if Charleston gentry wanted to spend August in the Hamptons, they could bring their cook along. No longer -- and South Carolina's delegates were outraged. In addition, they objected that New England states let black men vote and tolerated abolitionist societies. According to South Carolina, states should not have the right to let their citizens assemble and speak freely when what they said threatened slavery.

Other seceding states echoed South Carolina."Our position is thoroughly identified with the institution of slavery -- the greatest material interest of the world," proclaimed Mississippi in its own secession declaration, passed Jan. 9, 1861."Its labor supplies the product which constitutes by far the largest and most important portions of the commerce of the earth. . . . A blow at slavery is a blow at commerce and civilization."

The South's opposition to states' rights is not surprising. Until the Civil War, Southern presidents and lawmakers had dominated the federal government. The people in power in Washington always oppose states' rights. Doing so preserves their own....