EVER since the Continental Congress proclaimed the independence of the American colonies to candid world, the Declaration of Independence has formed part of the political thought and feeling of the American people. Unchanged in language through the years, the Declaration nevertheless has had a changing meaning for different groups of Americans, and one generation has often viewed it with a different feeling or emphasis from another. By the i820'S, for example, when the Declaration was read at Fourth of July celebrations, Jefferson's charges against an iniquitous George III no longer stirred the same feelings they did in I776. And the preamble, more enduring than the invective against the British king, has been a wellspring of imposing phrases for a variety of men and women with a mission. The history of the changes in thinking and feeling about the Declaration, and the story of the way in which politicians, reformers, and others have appealed to it in support of a variety of causes, are long ones, touching many of the major issues of American life. As in much historical writing, however, a few key points give form to an otherwise shapeless story. One such critical point centers in the years of the Missouri controversy, I8I9-I821, when Congress, no longer able to avoid the problem, threshed out, for a few years, the future of Negro slavery in America. One of the authorities appealed to in the debates was the Declaration of Independence. For the first time in our history its preamble was examined and analyzed, praised or criticized, in large-scale fashion. Some of the congressmen took as their text the Declaration's statement that all men are created equal and endowed with certain unalienable Rights. One of these rights was that of liberty. How, it was asked, could Negro slavery be reconciled with man's right to Life, Liberty and the pursuit of Happiness? Other passages of the Declaration were invoked, and the question of its meaning became part of the controversy. From the vantage point of the present it is difficult to write about the role of the Declaration in these debates without taking sides. George Dangerfield, for example, in describing the irreverent attitude toward the Declaration shown by Senator Nathaniel Macon of North Carolina, wrote that the Declaration was part of the spiritual fabric of the American Republic;