By Jesse Jackson

(CNN) -- A shantytown of plywood and pride, defiance and hope, Resurrection City was, 50 springtimes ago, the capital of Rev. Dr. Martin Luther King, Jr.'s last crusade for peace and justice -- the Poor People's Campaign.

We were a nonviolent, multiracial army of the dispossessed from across the country who had traveled to Resurrection City, built on the National Mall in Washington to demand that our elected representatives stop the killing and waste in Vietnam and begin the healing at home. We were America's shunned, discarded and invisible, no longer willing to stay silent and unseen.

We arrived with determined spirits and heavy hearts. Just four weeks before, King had been assassinated in Memphis, Tennessee, as he prepared to march with that city's striking sanitation workers before leading us to Washington for the people's war on poverty.

Fifty years later, a new movement of the locked out is rising. It is right on time. Everything we worked for -- and too many of us died for -- during the civil rights movement is under attack. Voting rights, women's rights, workers' rights, access to affordable health care, housing, education, the air we breathe and the water we drink are in peril.

On May 14, the new Poor People's Campaign: A National Call for Moral Revival will begin 40 days of protests and demonstrations in Washington and at least 30 states, seeking, in the spirit of Martin Luther King, an end to systemic poverty, racism and war.

Rooted in faith, love and a rock-solid belief and commitment to nonviolence, the campaign co-chairs are two incredible patriots, the Rev. Dr. Liz Theoharis of the Kairos Center for Religions, Rights, and Social Justice at Union Theological Seminary and the Rev. William Barber, president of Repairers of the Breach, a nonpartisan social justice organization.

When the new Poor People's Campaign hits the streets, I will proudly join them.

I was appointed city manager of Resurrection City -- an honor and a heartache -- by King's successor, the Rev. Ralph Abernathy, just before it opened on the National Mall in Washington on May 12, 1968.

For 42 mostly rain-drenched and mud-covered days, Resurrection City was home to thousands of the poorest of the poor, doing their best to prick the conscience of America and force action against the sin of grinding poverty in the richest nation on earth.

We were a coalition of conscience: poor blacks from the Deep South and the South Side of Chicago, impoverished whites from the hills and hollows of Appalachia, Native Americans from the Dakotas, Mexican-American farmworkers from the Southwest and California and Puerto Ricans from San Juan and New York.

Then and now, poverty haunts and hurts so many across lines of color, religion and region. Today, according to the US Census, nearly 41 million Americans live in poverty.

Contrary to stereotype, most poor people in the United States are not black or brown. They are white, young and female.

And most poor people work -- hard. They catch the early bus. They clean our streets, collect our trash, cook our food, wash our dishes, pick our fruits and vegetables and care for our elderly and our children.

The children suffer the most -- if they survive. The United States has the highest rate of infant mortality in the developed world. According to a report prepared by the Poor People's Campaign and census data, nearly 40% of our children will spend one year in poverty before they turn 18. The US spends less than 10% of its budget on children and 54% on the military.

More than 50 years ago, Martin Luther King said America desperately needed a "revolution of values." Our country is still in need of one and the Poor People's Campaign: A National Call for Moral Revival is a crucial moment in bringing it about.

In the months and weeks leading up to the Poor People's Campaign in 1968, many in power stopped listening to King. Longtime friends and allies turned on him -- the government, the press, the Democratic Party, his fellow civil rights leaders and black ministers who closed their pulpits to him. They told him to stay in his lane and not bother himself with issues of war and economic justice.

But the plight of the poor was too dire, the words of the Bible too clear, the war in Vietnam too immoral for King to listen. The only thing that stopped him was the assassin's bullet.

As we gathered in Washington weeks later, we were still in profound shock and deep grief. Many of us, I'm sure, were suffering from PTSD. Still, we pushed on. We owed it to the man we called Doc.

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On June 5, 1968, word quickly spread through Resurrection City that another unspeakable tragedy had befallen the country just a few weeks after King's murder.

We learned that Sen. Robert F. Kennedy had been assassinated in California.

On top of the constant rain and ankle-deep mud, the news was almost too much to bear. Depression and despair swept through us. I climbed into the back of a pickup truck and searched the faces of my dejected brothers and sisters -- black and white. They were staring back at me, looking to me for direction and hope.

I had nothing to give them -- no money, no train fare, no food.

Then I remembered hearing Doc telling a group of young people never to forget, "You are somebody."

So, I took a deep breath and began a mantra I have recited ever since.

"I am somebody," I said, asking the crowd to repeat after me.

"I may be poor, but I am somebody.

"I may be unskilled, but I am somebody.

"I may be on welfare, but I am somebody.

"I may be black or Mexican-American, but I am somebody."

A few weeks later, in a haze of police tear gas and confusion, Resurrection City was dismantled, and Martin Luther King's last crusade faded largely to forgotten history -- until now.

I will be there and be part of the new Poor People's Campaign as it begins and sustains six weeks of events to affirm and embody principles of nonviolence, economic justice and moral direct action. I have never put away my marching shoes. The memory of Martin Luther King won't let me, not until, as he quoted from the book of Amos in his legendary "I Have a Dream" speech, "justice rolls down like water and righteousness like a mighty stream."