John Avlon is a CNN senior political analyst and anchor. The opinions expressed in this commentary are his own. View more opinion articles on CNN.

(CNN) Every Southerner knows the truth of William Faulkner's words: "The past is never dead. It's not even past."

History hangs over Southern politics with a heaviness less known in the North. While it is a lazy northern stereotype to dismiss the South as irredeemably racist, the legacy of slavery, the Civil War and segregation plays a disproportionate role in Southern politics.

Just take a look at the high-stakes Senate runoff occurring Tuesday and a far less noticed but almost equally impactful judicial nomination to fill a lifetime federal court seat in North Carolina.

Let's start with the biggest federal race left in the nation, the Mississippi senate runoff between incumbent Republican senator Cindy Hyde-Smith and former Democratic congressman and Clinton agriculture secretary Mike Espy. First, a reality check: Mississippi hasn't sent a Democrat to the US Senate since the 1980s. Donald Trump beat Hillary Clinton here by an almost 18-point margin in 2016.

But after Doug Jones shocked the world with his Senate win over Roy Moore in Alabama all things seem possible, if not likely. CNN's Harry Enten estimates that Espy will need to pull more than 23% of the white vote and see record African-American turnout to pull out a win.

Given that Espy would be the first African-American senator from the state since Reconstruction, the second half of that requirement does not seem like mission impossible. But the need for a historically large chunk of the white vote reveals the ghost of the Civil War that huddles in the wings of the Senate race. And Senator Hyde-Smith keeps bringing the subject back by her words and actions.

The first incident in this primary was in the form of an odd joke that doesn't travel for good reason: the senator made a comment about be willing to take a front row seat at a "public hanging" if one of her prominent supporters invited her. Lynching humor isn't really a thing for obvious reasons and the fact that this phrase slipped off her tongue speaks to the way the darkest legacies of the South can endure in phrases that white folks say without thinking.

More culpable to my mind was the social media post the senator made after visiting the home of the traitorous Confederate President Jefferson Davis, wearing a confederate cap and calling it "Mississippi history at its best." This is a good example of the "heritage not hate" argument you often hear in the South -- but the truth is that it can be both.

This was not just a moment of historic enthusiasm on Hyde-Smith's part. CNN's K-File found that she sponsored a resolution to honor the last living daughter of a Confederate soldier in what she called "the War Between the States," while the Washington Post found she'd sponsored a resolution to re-name a road the "Jefferson Davis Memorial Highway."

This is perhaps a reflection of the culture Hyde-Smith grew up in: the Jackson Free Press found she'd attended a so-called "segregation academy" in the 1970s -- a private all-white school established as part of so called "massive resistance" to desegregation championed by white citizens councils at the time.

All of this is just more evidence of why it's important to learn our history and use it to impose perspective on our political judgments today.

That's also why debates over judicial nominations can matter beyond simple questions of filling a vacancy. You probably haven't heard the name Thomas Farr, but he's a North Carolina lawyer who's been nominated to fill the longest open court seat in our country. So why is this controversial?

Farr cut his teeth working on the campaign of North Carolina's notorious Jesse Helms -- a conservative who crusaded against civil rights legislation. More recently he served as a lawyer representing North Carolina's attempts to roll back voting rights through the use of Voter ID (which the Richmond-based 4th Circuit said impacted African-American voters with "almost surgical precision.")

Perhaps most troubling, Farr represented the North Carolina state legislature in putting forward a racial gerrymandered map which had key elements struck down by the US Supreme Court.

With the Senate narrowly divided -- and Obama's African-American nominees for the seat never brought up for a vote -- all eyes will be on South Carolina's Tim Scott to see whether Farr's record on voting rights represents a serious concern for the Palmetto state's conservative, African-American senator.

While Tim Scott is the first African-American from a Southern state to serve in the Senate since Reconstruction, it's worth noting that South Carolina posited a more diverse statewide elected slate when he and then-Gov. Nikki Haley served in office than most liberal northern states.

History casts a long shadow and can shape culture in ways that aren't always apparent to residents of a particular state. But the stereotypes often break down upon closer inspection. The culture of the country doesn't entirely change when you drive from a red state to a blue state.

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In fact, it might amaze some casual political observers to know that Hillary Clinton won the counties where there are big cities in Southern states like North Carolina (Charlotte, Raleigh-Durham, Greensboro), South Carolina (Charleston and Columbia), Tennessee (Nashville and Memphis) and Alabama (Birmingham and Montgomery). Obviously, Trump won all these states. But it's evidence that the larger cultural divisions in our country are not red state versus blue state as much as urban versus rural. And according to CNN's Enten, Democrats gained 5% in their percentage of the vote in urban and suburban areas of the Deep South in the 2018 midterms compared to the 2016 presidential election.

None of this means that Mike Espy should be considered a likely victor in Tuesday's Mississippi runoff. But the mere fact of a competitive Senate election between an African-American Democrat and a female Republican is a sign of civic progress that defies stereotypes and marks progress toward rebuking some of the ugliest aspects of our shared history.