In his brief time on the national stage Barack Obama has been compared to a host of great 20th-century orators, including John F. Kennedy and Ronald Reagan. But the most apt comparison may be to one of the greatest 19th-century orators: Frederick Douglass, the abolitionist leader.

In The New York Times recent examination of Mr. Obama’s career as a law school professor, a former student noted that he regularly evoked Douglass and not simply for his speaking skills but also for his “use of a collective voice that embraced black and white concerns.” For those seeking to get a clearer sense of what type of president Mr. Obama may be, his invocation of Douglass lends itself to several interpretations.

Douglass’s rise to prominence came from being a radical spokesman for abolition and a frequent critic of President Abraham Lincoln for the slow pace in which he worked to end slavery. But that was the younger Frederick Douglass. The thinking of the older Douglass appears to have had a more significant impact on Mr. Obama’s political thinking and in particular his campaign rhetoric.

Take a look at a speech that Douglass delivered on April 14, 1876. It is one of the greatest and most misunderstood speeches in American history.

Speaking at the dedication of a monument to Lincoln in Washington, Douglass began his remarks by declaring that the 16th president was “preeminently the white man’s president, entirely devoted to the welfare of white men” and that African-Americans were “at best only his stepchildren.” On the surface it seemed to be a shocking indictment of the Great Emancipator.

But Douglass quickly pulled back on the rhetoric to show that such simplistic characterizations failed to do justice to the complexity of Lincoln the politician (just as calling him the Great Emancipator was empty hagiography).

For Douglass, what made Lincoln special was that he was able to end slavery not by the force of his words, but by the nuance of his political machinations. Lincoln married the call for abolition with the savvy of a politician who made his decisions based on what Douglass called “the sentiment of his country, a sentiment he was bound as a statesman to consult.” By these standards, even though he waited until more than a year and a half into the war to emancipate the slaves, Douglass argued that Lincoln “was swift, zealous, radical and determined.”

To Douglass’s mind Lincoln deserved to be honored not because he freed the slaves, but because of how he freed the slaves. For a man who had spent much of his career lambasting Lincoln for not being a more aggressive abolitionist, it was a startling acknowledgment. Douglass’s words were recognition that radicalism and even the most principled stands must be balanced with the often difficult and far less enthralling process of incrementalism and political compromise.

Some on the left would like Mr. Obama to be like the younger Douglass, the firebrand reformist. But Mr. Obama’s rhetorical approach seems more attuned to the pragmatic observer of American politics that Douglass became.

A recent article in The New Yorker lays out well the manner in which Mr. Obama has kept one foot in the world of progressivism and one foot in the world of practical politics.

He campaigns on reforming a broken political process, yet he has always played politics by the rules as they exist, not as he would like them to exist. He runs as an outsider, but he has succeeded by mastering the inside game. He is ideologically a man of the left, but at times he has been genuinely deferential to core philosophical insights of the right.

Mr. Obama’s speechcraft is a reflection of these words. Largely eschewing strident partisanship (even at a time when Republicans are deeply unpopular), Mr. Obama is instead running against “Washington,” (which of course lumps both parties together). In 2004, he spoke of America not being a collection of red states or blue states but the United States. In his race speech, he acknowledged white grievances and black grievances, but then declared, “working together we can move beyond some of our old racial wounds, and that in fact we have no choice if we are to continue on the path of a more perfect union.”

Even when launching his campaign for the White House in the proverbial shadow of Lincoln in Springfield, Ill., he chose an unusual Lincoln quote, “Of strange, discordant, and even hostile elements, we gathered from the four winds, and formed and fought to battle through.” These words suggest a politician who is most focused on organizing disparate groups toward a larger goal.

There is a tension in Mr. Obama’s rhetoric; the veering between liberal ideology and solution-oriented politics; between, say, a younger Frederick Douglass and an older one. Indeed, in his book, “The Audacity of Hope” Mr. Obama references in equal measure Lincoln’s “firmness and the depth of his convictions” and the fact that his presidency was “guided by practicality.”

Mr. Obama appears to take lead from Douglass’s later analysis of Lincoln, who abolished slavery not by adopting radical means, but by taking a meandering, pragmatic course to achieve his goals. It’s a similar route to the one taken by Franklin D. Roosevelt, who even at the height of the Great Depression did not ram the New Deal down the throats of the American people but offered it to them in bite-size morsels.

On the stump, Mr. Obama is far more about poetry and sweeping rhetoric grounded in a powerful message of political change; but the admonition that one campaigns in poetry but governs in prose may well define an Obama presidency. Of course many will argue that in a partisan political culture, Mr. Obama must be prepared to carry a big, and occasionally sharp stick. That may be correct; but if Barack Obama wins the White House in November one can be reasonably sure that he will aim to prove these critics wrong--and prove the elder Mr. Douglass correct by seeking out the proper balance between what is right and what is possible.