The Rev. Martin Luther King Jr. and his wife, Coretta...

The Rev. Martin Luther King Jr. and his wife, Coretta Scott King, with New York City Mayor Robert F. Wagner at City Hall on Dec. 17, 1964, when King was declared an honorary New Yorker. Credit: Newsday / Alan Raia

At the Martin Luther King Jr. Memorial in Washington, a granite statue of the civil rights leader gunned down in Memphis 50 years ago this week stands in chiseled grandeur, gazing over the Potomac Tidal Basin. But the real monuments to King are a mile and a half east in the National Archives Building. There, within the marbled splendor, rest copies of the Voting Rights Act of 1965 and the Civil Rights Act of 1964.

The Voting Rights Act was the culmination of King’s march in Selma, Alabama. The televised march and the brutal reaction by police galvanized the nation and led President Lyndon Johnson to sign the bill into law. Before then, the ballot box was unreachable for most African-Americans in the South. Poll workers imposed bogus literacy tests, and political parties claimed to be private clubs inaccessible to African-Americans. Those who navigated these obstacles risked their lives: men like Lamar Smith, who was shot outside a Mississippi courthouse for registering people to vote, and women like Viola Liuzzo, who was killed by a shotgun blast while helping Selma marchers. The riverbeds of the South choked on bodies of those who deigned to exercise their right as citizens. The Voting Rights Act made denial of the right to vote unlawful as well as un-American.

The Civil Rights Act was the fruit of the March on Washington, where King delivered his “I Have a Dream” speech. Before then, Jim Crow was king. African-Americans had to plan trips with the precision of a desert crossing: how much food and water to bring, where and when to sleep, where to use the toilet. When challenged, restaurant and hotel owners had an insuperable response: Theirs was private property; they would serve whomever they wanted. The act upended this moral frame, saying the privacy of property ended once you opened your business to the public. The duty to serve one American applied to all.

These two acts are the pillars of the civil rights movement: One says how government should treat its citizens, the other how citizens should treat each other. In time, they changed not just the law, but how we think about fellow citizens, how we think about parties and property and dignity. These are the temples to the marches and sit-ins, the true monuments to King — and they’re cracking.

In 2008, the Supreme Court held that states can impose voter ID requirements. Numerous states strengthened ID laws — supposedly to prevent voter fraud, but often to suppress minority turnout. A Wisconsin staffer reported of legislators “giddy” over the prospect of disenfranchising voters through ID laws. Until the practice was invalidated, North Carolina required those forms of identification least available to African-Americans. In 2013, five justices struck down a key part of the Voting Rights Act, believing it no longer necessary. “Things have changed,” they said.

They certainly have. Once, publicly trafficking in racist conspiracies was disqualifying. Now it is a vehicle to the presidency. Once, unqualified support for public accommodation laws was the norm. Now skeptics can become U.S. senators. The court is considering a case asking whether a baker can refuse to prepare a wedding cake for a homosexual couple. Depending on how the court rules, it might not be a far step between refusing a gay couple to refusing an interracial one.

On the 50th anniversary of King’s death, we should attend to the health of his monuments. Not the granite ones, which, though beautiful, remain silent and immutable, but the ones that live when we walk into the polling station, when we sit in the coffee shop.

Darrell A.H. Miller is a professor of law at Duke University.