Anyone who's taken Psychology 101 will be familiar with the concept of cognitive dissonance -- stress caused by attempts to reconcile conflicting beliefs or deal with new information that contradicts an existing view. It afflicts smart conservatives who want to believe George W. Bush was a good president or Glenn Beck is an incisive thinker, as well as sensible liberals who feel they should respect Al Sharpton.

In the 1990s, a white suburban jury's acquittal of Los Angeles police department thugs filmed beating Rodney King caused civil unrest. Black thugs filmed nearly killing Reginald Denny during the subsequent riots weren't convicted either. These were similar events with similar outcomes, yet they bred conflicting reactions from conservatives and liberals, as well as white and black people.

Two decades later, the acquittal of conservative icon (and thug) George Zimmerman for stalking, then killing an unarmed Trayvon Martin isn't really the same as Derrin Wilson's exoneration in the death of Michael Brown, who's no "gentle giant" and shouldn't be anyone's hero. But, once again, different audiences have had opposite reactions.

Conservatives need to accept that police who kill minorities -- from Luis Rodriguez, murdered on video in Oklahoma in February, while not resisting arrest, to Eric Garner, choked to death on video in New York, while barely resisting arrest -- aren't always paragons of law enforcement. At the same time, liberal activists shouldn't dismiss ex-NBA star Charles Barkley's point that looters are "scumbags" and his sensible assertion that many minority neighborhoods would be the "Wild West" without a police presence.

Not all black men killed by the police are martyrs, most law enforcement officers are dedicated public servants and each of these "he said, he's dead" tragedies needs to be assessed on its own merits. Regardless, it was heartening to see students from several Fairfield County high schools take enough interest in social justice to walk out of school to protest the exoneration of Garner's killers.

Without slighting law enforcement overall, these students called attention to the fact that racism and police brutality remain serious problems. As Benjamin Franklin said, "Justice will not be served until those who are unaffected are as outraged as those who are."

Also encouraging was a Colorado student walkout protesting plans to politicize their high school curricula by removing references to America's historical oppression of minorities and the poor. Students and teachers rejected Republican school boards' desire to edit lesson plans and censor history to reduce the sort of cognitive dissonance that might cause students to question nationalism, authority and free-market economics.

Colorado conservatives objected to "liberal" versions of events that might be "historically true," but could turn students against "companies, corporations and wealthy Americans." Student protest leader Ben Smith was more focused on integrity and reality, asserting that, "Negative parts of American history aren't necessarily unpatriotic. We need to know these things, so we don't repeat them."

Although it's mildly surprising that students in mildly liberal Colorado stood up for the integrity of their textbooks, it was shocking when school boards in conservative Tennessee enraged the GOP National Committee by rejecting right-wing efforts to edit out some of the darker parts of American history to make the curriculum less "leftist."

Not surprisingly, the Texas Board of Education has put a conservative stamp on its history programs, stressing the merits of capitalism and Republicans, as well as the founding fathers' commitment to Christianity and contempt for church/state separation. This is just what you'd expect in a state that's still unsure whether to teach evolutionary biology or to use the official science textbook of the Bible Belt -- the Book of Genesis.

American exceptionalism demands that our history be glorious, our actions be blameless and Americans always be "the good guys." This continues to make the teaching of U.S. history controversial. For example, most Americans view the Alamo as a battle for freedom, but one of the proximate causes of the war for Texan independence was Mexico's abolition of slavery, which Southern immigrants to Texas found intolerable.

Americans have always been a bit irony-impaired. This is a country in which the line "All men are created equal" was penned by a slave owner, and our Constitution specifies that black men are three-fifths of a person. Our treatment of Native Americans has been genocidal, and Andrew Jackson, whose Indian Removal Act (aka "The Trail of Tears") wiped out thousands of Indians, is considered one of our greatest presidents.

Americans also feel a great deal of cognitive dissonance regarding immigration. We're all immigrants and enjoy pretending that we welcome them, but this is self-serving mythology. When in our country's history have we ever welcomed immigrants? Think of the phrases "No Irish need apply," or "Irishmen and dogs: Keep off the grass." The only immigrants we've ever truly welcomed were Africans, who weren't arriving willingly.

American presidents have done some terrible things. Lincoln suspended habeas corpus during the Civil War, FDR interned thousands of Japanese-American citizens during WWII, and we're the only country ever to have dropped nuclear weapons on civilians. The Bush administration routinely tortured suspected terrorists, and President Obama's drone attacks have turned innocent women and children into collateral damage.

James Joyce described history as "a nightmare," and pretending ours is an exception would be unrealistic. Philosopher George Santayana said, "Those who cannot remember the past are condemned to repeat it," but even those who do remember it, repeat it anyway. At a minimum, what's required is remembering history honestly.

For example, America has developed a love affair with the antebellum South. For many of us, the more than 600,000 men who died in the Civil War were fighting over a romantic "Cause," so, naturally, there were no "bad guys." In truth, one side committed mass treason against the United States, killing fellow Americans to preserve "states' rights," which mainly involved the right to buy, sell, exploit and abuse fellow human beings. Robert E. Lee and Jefferson Davis were fortunate not to be hanged as traitors.

Shameful movies such as "Birth of a Nation" and "Gone With the Wind (classic films with vile messages) glorified slavery and the Ku Klux Klan and helped legitimize more than a century of Southern resistance to civil rights. I can't help wondering if we'd be a better nation today if we'd taken a more honest view of our past.

People of conscience (e.g., John McCain) are ashamed of the CIA torture report, as well as the way police occasionally treat minorities, but you can't just pretend that bad things never happen (unless you're Dick Cheney). The cognitive dissonance created by hiding from our past can't be mentally healthy in a nation already so ideologically divided.

We don't need to pretend that America is some utopian "City on a Hill" or "New Jerusalem" to feel we're one of the best countries that's ever been. We may not perfect, but we can be honest about our past, and still be proud of our history.

Greenwich native Mark Drought (markdrought4@gmail.com) is a senior editor at a Stamford IT firm, and has been an aviation journalist for McGraw-Hill Inc. and an adjunct English professor at the University of Connecticut-Stamford.