Editor's Note: (Peniel Joseph is the Barbara Jordan Chair in Political Values and Ethics and the founding director of the Center for the Study of Race and Democracy at the LBJ School of Public Affairs at the University of Texas at Austin, where he is also a professor of history. He is the author of several books, most recently "Stokely: A Life." The views expressed here are his.)
(CNN) Fifty years ago this week, the Rev. Martin Luther King Jr. gave the most important speech of his life at the Riverside Church in New York, denouncing the Vietnam War and connecting the American civil rights struggle with a larger, global movement for peace and human rights. Forty-nine years ago this week, King was shot dead in Memphis, Tennessee.
King's assertion that the United States was the "world's greatest purveyor of violence" threw down a political gauntlet that would frame the revolutionary path he would follow during the last year of his life. "The world now demands a maturity of America that we may not be able to achieve," King told a packed audience in Riverside's pews.
At first blush it may seem counterintuitive to elevate this speech above the watershed "I Have a Dream" speech delivered four years earlier, or the "Mountaintop" speech he would give on the eve of his death. But if King's address at the March on Washington for Jobs and Freedom made him into an American icon, his Riverside Church speech announced him as a genuine prophet for social justice, one who willingly sacrificed his hard-won status to defy an empire.
The 50th anniversary of this speech is a profound occasion to counter the selective memory with which America has retrospectively embraced King. As a nation, we -- especially our elected officials and political leaders -- only remember the parts of King that align with what we choose to emphasize: his robust embrace of America's democratic traditions going back to the founders. King's elegant lauding of "those great wells of democracy" in his Letter from Birmingham Jail remains a touchstone in our own time.
Yet King grew increasingly bold and courageous as he confronted systemic challenges to his dream of multiracial democracy, what he called a "beloved community." The proliferation of urban violence, rural poverty, institutional racism and war forced him to reconsider the extent that mere political reforms would lead to economic and racial justice for all.
In the year between the Riverside speech and his assassination, King became America's most well-known anti-war activist, assuming the mantle from Black Power firebrand Stokely Carmichael and in the process lending a Nobel Peace Prize winner's moral power to a peace movement struggling amid a political landscape where most still supported the war.
King's speech blamed the nation's Cold War-fueled ambitions for the faltering war against poverty, the policy jewel in Lyndon Johnson's Great Society. While resources to fund the war drained the nation's financial and moral capital, suffering and discord at home inspired riots that King characterized in another speech as "the language of the unheard."
For the first time in the Riverside speech, King connected a domestic civil rights movement with US foreign policy. He based his criticism of the war on a profound love for America, contrasting the "hopes" and "new beginnings" promised by a national anti-poverty crusade with the escalating death, violence and destruction in Southeast Asia.
Many blasted this decision as unwise and irresponsible. His criticism of the Johnson White House ended a once-close professional relationship that found him on the receiving end of presidential pens signing the Voting Rights Act in 1965. Once praised by mainstream political and civic leaders for his philosophy of nonviolence, King found himself vilified for calling for an end to the bombing of Vietnamese villages and the napalming of innocent children.
The Riverside speech's unpopularity -- fueled by its candid assessment of the shortcomings of American democracy -- is precisely what makes it King's most powerful and important speech.
King loved America enough to always be honest.
A political leader who dined with royalty and met with presidents at the White House found himself increasingly drawn to the plight of poor people around the world. His belief that black sharecroppers in the Deep South deserved the same consideration as intellectual and economic elites led to his championing a Poor Peoples Campaign that planned to descend on the nation's capital in May 1968 until Congress passed legislation that addressed growing inequality in America. After King's assassination that April, his widow and others tried to continue this work.
By the time King approached the pulpit at Riverside Church that early spring day in 1967 the gap between America's democratic ideals and its stubbornly unequal reality had, according to King, grown into an unconscionable chasm. There comes a time when "silence is betrayal," said King in words meant to admonish himself as much as the rest of the nation.
A half-century later, King's words continue to haunt our contemporary democratic imagination. At Riverside Church, King spoke of the need to "speak for those who have been designated as our enemies," words that resonate in our own time as much as they did in his. Ultimately, King's call for a "radical revolution of values" anticipated the scourge of economic inequality, racial injustice, religious intolerance and anti-immigrant sentiment that confronts American democracy in 2017.
Yet the radical King never abandoned his faith in America's capacity for social and political transformation. Near the end of his speech he spoke of the "long and bitter — but beautiful — struggle for a new world" he proudly engaged in. It is a struggle that King willingly sacrificed his own life for one year later and one that continues to this day.