It was a warm spring afternoon when Martin Luther King addressed tens of thousands gathered in front of the Lincoln Memorial, the largest gathering to date in the growing struggle for civil rights.

King rallied the crowd with his stirring refrain: "Give us the ballot!" He called for the government, white liberals, white Southerners, and finally the African-American community to work, struggle, and sacrifice to achieve a more just, free, and integrated nation.

But more than 50 years later, few remember this speech delivered at the "Prayer Pilgrimage for Freedom" on May 17, 1957. But the nation and the world are very much aware of a speech King gave only six years later at the very same location.

Why do we remember the 45th anniversary of the "March on Washington for Jobs and Freedom," while largely ignoring a very similar march that occurred six years earlier?

For one, King's speech was better. "Give us the Ballot" is no "I Have a Dream." The speech helped cement the moment in our national consciousness.

Second, the media coverage was much more extensive in 1963 than it had been in 1957.  Thanks in part to media coverage, the August 1963 march became part of the national consciousness.

Also, the crowd was much larger. While exact attendance figures at such events are always disputed, the 1957 march drew around 20,000, while the 1963 event drew between 200,000 and 300,000 people.

But the biggest difference between 1957 and 1963 was not the quality of the speech, the media coverage, or the size of the crowd. No, these were mere consequences of a much bigger transformation.

In 1957, the march was an attempt to rally the nation around an issue. Building on the Brown vs. Board of Education decision and the Montgomery bus boycott, civil rights leaders tried to leverage their strength to exert pressure on the federal government. But in 1957, there was not yet a national grassroots movement for civil rights.

Although local communities were stirring and organizing, the 1957 march was at the dawn of the movement, and therefore did not galvanize the strength that would be obvious just six years later.

So what changed between 1957 and 1963?

1. The Sit-In Movement of 1960, which galvanized college students throughout the south to submit to physical abuse and arrest to ensure integrated lunch counters in southern dime stores.

2. The founding of the Student Nonviolent Coordinating Committee, which provided a network of young civil rights activists who would be on the front lines of the movement throughout the 1960s.

3. The Freedom Rides, which forced the federal government to enforce national laws that called for integrated bus services on intrastate travel. When black and white riders were abused, beaten, had one of their buses firebombed, and eventually filled the jails of Mississippi, the nation became more aware of the courage of the African-American community and the horrific violence of segregationists and white supremacists.

4. The Birmingham Movement, where Bull Conner unleashed firehoses and police dogs on African-American children, leading many in the nation to the conclusion that integration and racial justice could be delayed no longer.

By 1963, a grassroots civil rights movement had emerged. The march represented the culmination of day-to-day organizing in small towns and cities throughout the South. Many in the crowd had been beaten, arrested, abused, lost jobs, and were reviled because of their courageous work for social change.

So we remember King's "I Have a Dream" speech and the 1963 March on Washington not because of a grand event or even a great speech, but because it was an event that galvanized grassroots power built throughout the South and throughout the nation. The 1963 march was not a tactical PR move, but a culmination of a movement that transformed our nation.

As we watch people fill arenas in Denver and the Twin Cities, many will be inspired as we listen to compelling speeches from both Democrats and Republicans. But remember, a collection of tens of thousands of people responding to a grand speech never changed anything, anymore than the millions who will gather for NFL and college football games this fall will have a great social impact on our world.

Speeches and conventions are fine, but the real social change happens on the ground, in our local communities, person-to-person, small group to small group, neighborhood by neighborhood. Jesus didn't usher in the kingdom of God at the Sermon on the Mount, but through a ragged group of disciples who changed the world.

During this election season and beyond, as Christ-followers, I pray we don't get so swept away by a few great speeches that we fail to do the hard work in our local communities that can help "God's kingdom come, God's will be done, on earth as it is in heaven."

Local organizing made all the difference between 1957 and 1963. In 2008, local organizing will determine if we have a national "feel-good" moment when we elect an African-American president or a female vice president, or whether we experience a transformed nation and a transformed world.

Troy Jackson is senior pastor of University Christian Church in Cincinnati, a graduate of Princeton Theological Seminary, and earned his Ph.D. in United States history from the University of Kentucky. He is author of Becoming King: Martin Luther King, Jr. and the Making of a National Leader, and a participant in Sojourners' Windchangers grassroots organizing project in Ohio to work on the Vote Out Poverty Campaign.