ON JAN 1, 1863, Abraham Lincoln promulgated his Emancipation Proclamation. A document whose grand title promised so much but whose bland words delivered so little, the Emancipation Proclamation has been an enigma ever since. Like contemporaries, historians have been unsure whether to condemn it as a failure of idealism or applaud it is as a triumph of realpolitik.

The American people have also been of two minds. Few officially sponsored commemorations currently mark the day slaves once called "The Great Jubilee;" instead, of late, black people have taken to celebrating their liberation on "Juneteenth," a previously little-known marker of the day in June when the Union Army arrived in Texas and liquidated slavery in the most distant corner of the Confederacy. Unlike our other icons -- the Declaration of Independence and the Constitution -- the Proclamation is not on regular display at the National Archives, which makes its current exhibition all the more significant.

The very ambiguity of the Emancipation Proclamation has also made Lincoln's edict the focal point of conflicting notions about the role of high authority, on one hand, and the actions of ordinary men and women, on the other, in shaping American society.

Lincoln's proclamation, as has often been noted, freed not a single slave. It applied only to the slaves in territories then beyond the reach of federal authority. It specifically exempted Tennessee and Union-occupied portions of Louisiana and Virginia, and it left slavery in the loyal border states -- Delaware, Maryland, Kentucky and Missouri -- untouched. Indeed, the Proclamation went no further than the Second Confiscation Act of July 1862, which freed all slaves who entered Union lines professing that their owners were disloyal, as well as slaves who fell under federal control as Union troops occupied Confederate territory.

Moreover, the Emancipation Proclamation rested upon the president's power as commander-in-chief and was subject to constitutional challenge. Even Lincoln recognized the limitations of his ill-defined wartime authority, and, as his commitment to emancipation grew firmer in 1863 and 1864, he insisted upon the passage of a constitutional amendment to affirm slavery's destruction.

What then was the point of the Proclamation? It spoke in muffled tones that heralded not the dawn of universal liberty but the compromised and piecemeal arrival of an undefined freedom. Indeed, the Proclamation's flat prose, ridiculed by abolitionists as having the moral grandeur of a bill of lading, suggests that the true authorship of Afro-American freedom lies elsewhere -- not at the top of American society but at the bottom.

From the first guns at Sumter, the strongest advocates of emancipation were the slaves themselves. Lacking political standing or public voice, forbidden access to the weapons of war, slaves tossed aside the grand pronouncements of Lincoln and other Union leaders that the sectional conflict was only a war for national unity and moved directly to put their own freedom -- and that of their posterity -- atop the national agenda. Steadily, as opportunities arose, slaves risked all for freedom by abandoning their owners, coming uninvited into Union lines and offering their help as laborers, pioneers, guides and spies.

Slaves forced federal soldiers at the lowest level to recognize their importance to the Union's success. That understanding traveled quickly up the chain of command. In time, it became evident even to the most obtuse federal commanders that every slave who crossed into Union lines was a double gain: one subtracted from the Confederacy and one added to the Union. The slaves' resolute determination converted many white Americans to the view that the security of the Union depended upon the destruction of slavery. Eventually, it tipped the balance in favor of freedom, even among those who had little interest in the question of slavery and no love for black people. No one was more responsible for smashing the shackles of slavery than the slaves themselves.

What of the Great Emancipator and his Proclamation? Lincoln was no friend of slavery. He believed, as he said many times, that "if slavery is not wrong, nothing is wrong." But, as president, Lincoln believed he had a constitutional obligation to protect slavery where it existed. Shortly before his inauguration, he offered to support a proposed constitutional amendment prohibiting any subsequent amendment to "abolish or interfere . . . with the domestic institutions of the states, including slavery."

As a wartime leader, Lincoln feared the disaffection of the loyal slave states, which he understood to be critical to the success of the Union. Lincoln also doubted that black people could live as equals in American society and, like many white Americans from Thomas Jefferson to Henry Clay, he favored the colonization of former slaves in Africa or elsewhere.

Lincoln responded slowly to demands for emancipation as they worked their way up the military chain of command and as they resonated in Northern public opinion. He revoked the field emancipations of Union generals John C. Fremont in July 1861 and David Hunter in April 1862, who invoked martial law to liberate slaves in Missouri and South Carolina, respectively. In late September 1862, even while issuing the preliminary emancipation proclamation, he continued to call for gradual, compensated emancipation in the border states and compensation for loyal slaveholders elsewhere. The preliminary proclamation also reiterated his support for colonizing freed slaves "upon this continent or elsewhere."

As black laborers became essential to the Union war effort and as demands to enlist black men in the federal army mounted, the pressure for emancipation became inexorable. On Jan. 1, Lincoln fulfilled his promise to free all slaves in the states still in rebellion. Had another Republican been in Lincoln's place, that person doubtless would have done the same. Without question, some would have acted more expeditiously and with greater bravado. Without question, some would have acted more cautiously with lesser resolve. In the end, Lincoln did what needed to be done. His claim to greatness rests upon his reading of the moment.

Thus, when Lincoln finally acted, he moved with confidence and determination. He stripped the final Proclamation of any reference to compensation for former slaveholders or colonization for former slaves. He added provisions that allowed for the service of black men in the Union army and navy, opening the door to the eventual enlistment of nearly 200,000 black men. Once slave men entered the Union army, they were free and they made it clear they expected their families to be free too. In time, Congress confirmed this understanding and in March 1865 provided for the freedom of the immediate families of all black soldiers. Lincoln's actions, however tardy, gave force to all that slaves had risked. After Jan. 1, 1863, the Union army was an army of liberation.

Lincoln understood the importance of what he had done, both politically and morally. Having determined to free the slaves, he declared he would not take back the Emancipation Proclamation even when military failure and political reverses threatened that policy. He praised the role of black soldiers in preserving the Union and liquidating chattel bondage. To secure the freedom that his Proclamation had promised, Lincoln promoted the passage of the 13th Amendment, although he did not live to see its ratification.

The Emancipation Proclamation's place in the drama of emancipation is thus secure. To deny it is to ignore the deep struggle by which freedom arrived. It is to ignore the soldiers who sheltered slaves, the abolitionists who stumped for emancipation and the thousands of men and women who -- like Lincoln -- changed their minds as slaves made the case for universal liberty. In this sense, slaves were right in celebrating Jan. 1 as the Day of Jubilee. The Emancipation Proclamation reminds us that real change derives only from the actions of the people and that political leadership finds its truest moment when it acts upon the authentic will of the people.

Ira Berlin is professor of history at the University of Maryland and co-editor of "Free at Last" (The New Press).