(CNN) Another February has passed, and once again too many Americans view Black History Month as a footnote, impacting African-Americans but insignificant to the greater country. Slavery was not merely a chapter in US history, it was an institution that created America. However, children are not learning about slavery, its impact, and its relevance today, and it shows.

Our failure to address a legacy of enslavement and racial oppression makes the US ill-equipped to deal with present-day injustices and challenges.

The Southern Poverty Law Center has sounded the alarm by releasing a report, "Teaching Hard History: American Slavery." SPLC insists the country needs an intervention, and urges states, school districts and textbook publishers to stop avoiding the hard truths about slavery. According to the report, the white supremacy and racism afflicting America today stem from the racial theories used to justify the enslavement of African and native peoples.

"Slavery's long reach continues into the present day," the SPLC says. "The persistent and wide socioeconomic and legal disparities that African-Americans face today and the backlash that seems to follow every African-American advancement trace their roots to slavery and its aftermath. If we are to understand the world today, we must understand slavery's history and continuing impact."

The United States teaches slavery in a way that lacks historical context, accentuates historical positives while ignoring a troubling legacy, and covers a difficult past only to the extent those problems were resolved, the SPLC notes.

Schools teach slavery as a purely Southern phenomenon, and focus exclusively on white experiences, with scant attention to the impact on black people. Some teachers lead students in re-enactments and role-playing exercises involving slave auctions and the Middle Passage — the forced journey across the Atlantic in which at least 2 million Africans died - which could traumatize children and impede learning.

Further, history curricula ignore the role of white supremacy that justified racial violence against African-Americans, and the connections between the past and the present.

A survey of high school seniors, social studies teachers, state history curriculum standards and widely used textbooks tells the story. The report found that only 8% of high school seniors identified slavery as the cause of the Civil War and 68% were unaware a constitutional amendment ended slavery. Moreover, fewer than one-quarter could identify how specific parts of the Constitution benefited slave masters.

Although more than 90% of teachers claim they are "comfortable" teaching slavery to students, 58% of teachers found textbooks inadequate, and 40% said their state provides inadequate support.

SPLC developed a rubric for textbooks to determine how comprehensively they covered slavery and the plight of enslaved people. The best textbook the organization reviewed achieved a score of 70%, with the average textbook earning a paltry 46%.

Of course, states have their own standards for textbooks. But none of the 15 sets of standards that were analyzed by the SPLC addressed how white supremacist ideology justified the institution, and "most [state standards] fail to lay out meaningful requirements for learning about slavery, about the lives of the millions of enslaved people, or about how their labor was essential to the American economy."

This clear disconnect from reality is what happens when the school system fails to teach how the trading of human beings fueled US capitalism and the Industrial Revolution, and made America a global economic powerhouse.

Think about what would happen if students opened a textbook and found that in 1860, nearly 4 million enslaved people of African descent were worth $3.5 billion — more than the nation's railroads and manufacturing combined, and the most valuable single asset in America. Banks, corporations and universities profited from slavery, providing inherited wealth for whites, with centuries of unpaid wages for black labor, helping explain today's racial wealth gap.

With post-Civil War Reconstruction came black empowerment and federal troops to protect the newly emancipated in the South. When the troops withdrew, whites re-established slavery through the economic exploitation of sharecropping, criminalization of African-American men, black disenfranchisement, and a reign of domestic terror including lynchings, massacres and assassinations of black elected officials.

"In the late 19th and early 20th centuries, white Southerners looking to bolster white supremacy and justify Jim Crow reimagined the Confederacy as a defender of democracy and protector of white womanhood. To perpetuate this falsehood, they littered the country with monuments to the Lost Cause," wrote Ohio State University professor Hasan Kwame Jeffries in the report.

If young people don't understand the history behind racial tensions in America, they become adults who don't understand why NFL players kneel in protest against repeated racial injustices.

As students saw Charlottesville explode, they should have been able to call to mind history lessons on Jim Crow, a time when white supremacists erected Confederate monuments honoring the "Lost Cause."

The 1915 film "The Birth of a Nation" glorified the KKK and the Confederacy, and President Woodrow Wilson, who segregated the federal government, screened it at the White House, declaring, "It's like writing history with lightning. My only regret is that it is all so terribly true." Learning about Wilson's views on the Klan would help students understand why there was such an outcry by civil rights activists when President Donald Trump proclaimed there were "very fine people on both sides" in Charlottesville.

Without this historical knowledge, students cannot understand why 6 million African-American refugees fled the South between 1916 and 1960 in the nation's largest mass migration, or why we even needed a civil rights movement.

We are being forced to refight old civil rights battles. Wealthy landowners constructed race and white supremacy to "divide and conquer" and keep enslaved Africans and European indentured servants from banding together for economic justice. Poor Southern white men - whose labor was rendered obsolete and wages kept low by slavery -- fought and died to preserve the plantation police state.

Today, we see how racism manipulates the white poor and working class to believe people of color are the cause of their problems. Trump's anti-immigration policies of "the wall" and mass deportation for undocumented immigrants from nonwhite "shithole countries" harken back to the lawsadvocated a century ago by white supremacists and eugenicists to preserve "pure, unadulterated Anglo-Saxon stock," stop the "vast hordes" of brown people from Asia, and promote the illegal deportation of 600,000 US citizens of Mexican heritage.

Fifty years before Colin Kaepernick took a knee against police brutality, three athletes at the 1968 Summer Olympics in Mexico City - two African-Americans, one white Australian - protested against racial oppression with their iconic Black Power salute during the National Anthem. Just as these Olympians were shunned and subjected to death threats for their bold stance against injustice, today's NFL athlete-activists are criminalized, labeled ungrateful and un-American. That anti-racism protests engender more outrage than racial injustice demonstrates this nation must do better.

George Santayana famously said those who cannot remember the past are condemned to repeat it. Never will America address its fundamental challenges if it refuses to learn the lessons of history and teach its children well.

This commentary was originally published by CNN.com