It’s hard to search for America’s common ground without confronting the nation’s most divisive argument, especially if you are a New England yankee touring the Deep South.

I study a roadside historical marker in Decatur, Alabama – I’m one of those people who brakes for history – and learn that all but four buildings in the town were ordered destroyed under Union Army occupation. A sign in Selma tells a similar story of the story of the deliberate destruction the thriving city in 1865.

You’ll find no such stories of Civil War destruction north of Gettysburg. No wonder generations of Southerners have called it the War of Northern Aggression.

Another battle was fought in Selma a century later. I cross the Edmund Pettus Bridge on the anniversary of Bloody Sunday, the day Alabama police viciously attacked civil rights marchers. Shown on national TV, the scene outraged much of the country, galvanizing support for the Voting Rights Act of 1965.

This year’s bridge re-crossing is both a celebration of that victory and a protest against the current assault on voting rights being waged in some state capitals. I’m disappointed by how few white faces can be found among the marchers.

In Confederate Park in Memphis, I read the inscription on a statue of Jefferson Davis. It lists his offices – U.S. Congress, senator, secretary of war and, in large letters, president of the Confederate States of America. I read the summation at the bottom - “A True American Patriot” and the Yankee in me rebels: Anyone who violates his oath to defend the Constitution, who instead takes up arms against the constitutional government of the United States is a traitor, not a patriot.

I read another marker in New Orleans, marking the spot where a huge slave auction house sat. I read the markers along the route of the Selma-to-Montgomery march, led by the Rev. Martin Luther King Jr., now designated a National Historic Trail. Black history – which is every American’s history, really – is being told, if you listen for it.

It’s being told especially well in Memphis, behind the preserved façade of the Lorraine Motel. Respectful crowds – almost as many white faces as black, the day I visit – file quietly past the room where Martin Luther King last slept, look out the window at the balcony where he fell and, beyond that, the window from which the assassin’s shot was fired. Motel and the former rooming house across the street now house the National Civil Rights Museum, which tells the story of centuries of struggle for equality.

I visit the battlefield at Shiloh, where, in 1862, more Americans fell in one battle than in all the nation’s previous wars combined. I take a wrong turn on the battlefield tour and come upon a small brick home decorated with Confederate flags. A sign reading “Jesus” hangs from a cannon pointed at the street. For a few people, that war still isn’t over.

I’m no stranger to the South. My mother was born in Cotton Plant, Mississippi, and 67 years in New England failed to erase her southern accent. That may be one reason I quickly picked up an accent of my own over the five years I lived in Tennessee.

When I moved back to Massachusetts, I was surprised at the condescension I felt from a few people I met. Once they heard me talk, they acted like I was dumber than them. And, since I was a Southerner and white, I must also be a racist, it seemed. A lot of Northerners act like all Southerners are white, which would come as a surprise to Southerners like Martin Luther King.

Some Southerners have their own attitude problems. They make excuses for the past, wallow in victimization, confuse racism with heritage and see every liberal Northerner as an arrogant jerk.

The divide defines our politics as well as our attitudes. The shape of the old Confederacy appears in red on most election maps. Republicans and Democrats alike stoke racial resentments for their own partisan purposes. There’s even been loose talk of secession – in Texas after Barack Obama was elected and in California in the wake of Donald Trump’s victory.

But that’s just talk. We’re a long way from a civil war, just as we’ve come a long way on civil rights.

But the scars remain, and there’s still work to be done. In America, “One nation, indivisible” remains an aspiration, not a reality.

Rick Holmes can be reached at rick@rickholmes.net. You can follow his journey at www.rickholmes.net. Like him on Facebook at Holmes & Co, on Twitter @HolmesAndCo.