Every time Americans think they can forget about Ferguson, Mo., the town now synonymous with prejudice jumps back into the headlines with incidents like last week's shooting of two police officers. Ferguson keeps reminding us that racism remains an issue in this country, and we wonder when it will not be.

In his 1903 book The Souls of Black Folk, the African American sociologist W.E.B. Du Bois declared, "The problem of the 20th century is the problem of the color-line." A century later, one can't persuasively argue that nothing has changed. But race relations in America remain fraught.

A recent Wall Street Journal/NBC News poll found that just 35 percent of blacks and 40 percent of whites believe race relations are good. Many respondents were likely influenced by the violence following last year's killings of two unarmed black men - Michael Brown in Ferguson and Eric Garner in Staten Island, N.Y. - in confrontations with police.

After numerous protests of police mistreatment since Brown and Garner's deaths, a rally in Ferguson Thursday night ended with two police officers being shot and wounded. The attack occurred in the wake of a scathing Justice Department report alleging an infestation of racism within Ferguson's city government. Attorney General Eric H. Holder Jr. said it had become "routine" for Ferguson officers to violate the constitutional rights of residents. The report prompted the resignations of six public officials, including the city manager, the police chief, a municipal judge, and a court clerk.

Anyone who wanted to believe racism is just a Ferguson problem had that delusion blown up last week by a University of Oklahoma fraternity. A chapter of Sigma Alpha Epsilon was banned from the campus after a video found on the Internet showed its members chanting on a bus: "There will never be a n- at SAE. You can hang him from a tree, but he'll never sign with me."

Considering the frat brothers' relative youth, their behavior is even more disturbing as further evidence that the problem Du Bois noted 112 years ago not only persists, but is almost certain to remain an impediment to the equal treatment of Americans for many years to come. That's not to say further progress in race relations won't be made, but it's a recognition that the pace is too slow.

It might be different if people who should know better than to act like frat boys would consider how their words and actions can fuel racism. A congressman calling the first black president of the United States a liar in a public forum, for example, shows a level of disrespect that encourages racism. Ultimately, no law or decree can end racism; it will take the collective will of every American to bury what should be a relic of the past in a deep grave.