The White House recently whispered out the back door that President Obama would not appear in Pennsylvania next Tuesday at the ceremonies for the 150th anniversary of Abraham Lincoln’s Gettysburg Address. The political betting had been that this was a big-speech venue whose glow Mr. Obama would not want to miss. The higher-road expectation was that this particular Civil War anniversary required the presence of this particular American president. It’s not happening. The administration’s official attendee will be Secretary of the Interior Sally Jewell.

The White House offered no explanation beyond Jay Carney‘s bloodless reply to a reporter: “I think Americans will take the appropriate time to consider the speech that was delivered there. I would simply say that I have no updates on the president’s schedule.”

What was he supposed to say? Once the president—or whoever—decided he wouldn’t attend, no possible explanation was going to suffice for the Gettysburg no-show.

There is no inclination in this quarter to second-guess the White House’s rationale for not attending. And maybe it’s just as well we won’t hear Mr. Obama’s thoughts on the Gettysburg Address. Those words were about a renewal of the nation’s unity, and five years into the Obama presidency, the United States is about as politically divided as it can get. The division is so intense that Americans paint their political beliefs in one of two colors: blue or red.

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‘Lincoln at Gettysburg,’ painted by Fletcher C. Ransom in 1938. Getty Images

That this division exists in 2013, 150 years after Lincoln wrote those words, is ironic, to say the least. So it is unavoidable that any reflection on the anniversary of the ceremony at Gettysburg Cemetery in 1863 has to occur inside the context of the nation’s current presidency and what that presidency stands for.

At Gettysburg, Lincoln described the nation’s origin, its civil war and its future with a poetic concision not heard since the first chapter of Genesis. We do not call his words a speech, as in a farewell speech. It was an address delivered to all the American people at a pivotal moment to describe what he hoped would come after the war. He spoke of “unfinished business.”

All will agree that the unfinished business included Nov. 4, 2008, the day the American people elected a black man into their presidency. This came 54 years after the judicial branch decided in Brown v. Board of Education that racially segregated public schools were unconstitutional, and 43 years after the legislative branch passed the Voting Rights Act. “All men,” Lincoln said in the address’s first sentence, “are created equal.”

What Lincoln said next matters most for those living in the here and now, and who are so at odds over the nation’s direction and governing ideas.

In the moment before he spoke the address’s final, famous words—that government of, by and for the people “shall not perish from the earth,” he uttered what may be its most potent phrase. “This nation,” Lincoln said, will have “a new birth of freedom.”

Lincoln’s phrase, “a new birth of freedom,” suggests a radical freedom. The Civil War had shaken the nation out of its unfree state, and Lincoln was asserting that America would now pursue an even higher state of freedom. But what would be the shape and content of this radical American freedom?

The clue may be found in the one word favored in all presidents’ speeches—”we.” There is general agreement that “we” is shorthand for “We the People” of the U.S. Constitution’s Preamble. There is less consensus on what that phrase was intended to mean.

We know what President Obama thinks it means. In every speech given during his presidency, and in virtually every policy direction he has proposed in those speeches, it is clear that when Mr. Obama says “we,” he means the federal government acting at its seat of power in Washington, D.C.

For Mr. Obama, and many others, “We the People” means not the Union of sovereign states, the Union for which a civil war was fought, but the single political agency of the national government. Had he decided to show up Tuesday in Gettsyburg, Mr. Obama would have repeated his belief that American freedom flows forward from acts taken by one national government, itself defining and administering the collective will of some inchoate force called “we.”

It is impossible to imagine that Lincoln thought that the “new birth of freedom” made possible by the sacrifice at Gettysburg would become almost solely the result of choices made by modern America’s hugely aggrandized unitary state.

Lincoln was not “anti-government” and obviously not averse to federal power. But surely Lincoln, the Illinois frontier lawyer who spoke of a nation “conceived in liberty,” would be aghast to see the piling up of laws, rules, must-dos and must-not-dos that pervade the American workplace, judicial code, commerce, health care, education, and even, of all things, common speech.

Lincoln’s purpose in reuniting the nation was to elevate, not diminish, freedom for “men,” for individuals. Barack Obama’s election to the presidency personifies Lincoln’s purpose. We will wait for some future president to renew the full meaning of Lincoln’s ideas at that Gettysburg battlefield.

Write to henninger@wsj.com