Seven score and 10 years ago, Abraham Lincoln delivered his sacred speech on the meaning of free government. Edward Everett, a former secretary of state and the principal speaker for the consecration of the Gettysburg cemetery, instantly recognized the power of the president's 272 words.

"I should be glad, if I could flatter myself," Everett wrote to Lincoln the next day, "that I came as near to the central idea of the occasion, in two hours, as you did in two minutes."

Barack Obama is not scheduled to be present at Gettysburg on Tuesday to commemorate the 150th anniversary of the address. Maybe he figured that the world would little note, nor long remember, what he said there. Maybe he thought the comparisons with the original were bound to be invidious, and rightly so.

If that's the case, it would be the beginning of wisdom for this presidency. Better late than never.

Mr. Obama's political career has always and naturally inspired thoughts about the 16th president: the lawyer from Illinois, blazing a sudden trail from obscurity to eminence; the first black president, redeeming the deep promise of the new birth of freedom. The associations create a reservoir of pride in the 44th president even among his political opponents.

But, then, has there ever been a president who so completely over-salted his own brand as Barack Obama? "I never compare myself to Lincoln," the president told NBC's David Gregory last year. Except that he announced his presidential candidacy from the Old State Capitol building in Springfield, Ill. And that he traveled by train to Washington from Philadelphia for his first inauguration along the same route Lincoln took in the spring of 1861. And that he twice swore his oaths of office on the Lincoln Bible. "Lincoln—they used to talk about him almost as bad as they talk about me," he said in Iowa in 2011.

No, this has not been a president who has ever shied away from grandiose historical comparisons. If George W. Bush reveled in being misunderestimated, Mr. Obama aims to be selfhyperadulated. "I would put our legislative and foreign policy accomplishments in our first two years against any president—with the possible exceptions of Johnson, FDR, and Lincoln," the president told "60 Minutes" in 2011. Note the word possible.

But now that has started to change. The president has been humbled; he's pleading incompetence against charges of dishonesty; the media, mainstream as well as alternative, smell blood in the water.

And his problems on that score are just beginning: ObamaCare is really a political self-punching machine, slugging itself with every botched rollout, missed deadline, postponed mandate, higher deductible, canceled insurance policy and jury-rigged administrative fix. John Roberts, we hardly knew you: Your ObamaCare swing vote last year may yet turn out to be best gift Republicans have had in a decade.

All this will force even liberals to reappraise the Obama presidency. Lincoln's political reputation went from being "the original gorilla" (as Edwin Stanton, his future secretary of war, once called him) to being celebrated, in the words of Ulysses Grant, as "incontestably the greatest man I have ever known." Obama's political trajectory, and reputation, are headed in the opposite direction: from Candidate Cool to President Callow.

That reappraisal is going to take many forms, not least in the international goodwill Mr. Obama's presidency was supposed to have brought us. But since the occasion of this column is the Gettysburg sesquicentennial, it's worth turning to the question of the president's once-celebrated prose.

Abraham Lincoln spoke greatly because he read wisely and thought deeply. He turned to Shakespeare, he once said, "perhaps as frequently as any unprofessional reader." "It matters not to me whether Shakespeare be well or ill acted," he added. "With him the thought suffices."

Maybe Mr. Obama has similar literary tastes. It doesn't show. "An economy built to last," the refrain from his 2012 State of the Union, borrows from an ad slogan once used to sell the Ford Edsel. "Nation-building at home," another favorite presidential trope, was born in a Tom Friedman column. "We are the ones we have been waiting for" is the title of a volume of essays by Alice Walker. "The audacity of hope" is adapted from a Jeremiah Wright sermon. "Yes We Can!" is the anthem from "Bob the Builder," a TV cartoon aimed at 3-year-olds.

There is a common view that good policy and good rhetoric have little intrinsic connection. Not so. President Obama's stupendously shallow rhetoric betrays a remarkably superficial mind. Superficial minds designed ObamaCare. Superficial minds are now astounded by its elementary failures, and will continue to be astounded by the failures to come.

Is there a remedy? Probably not. Then again, the president's no-show at Gettysburg suggests he might be trying to follow Old Abe's counsel in a fruitful way: "Better to remain silent and be thought a fool," the Great Emancipator is reported to have said, "than to speak and to remove all doubt."