Washington ? The pressure’s on for Barack Obama, orator.

History wants something for the ages in his Jan. 20 inaugural speech. Not just pretty words that melt like gumdrops but something that will settle in the nation’s soul and be worth making schoolchildren memorize 100 years from now.

Americans want something for the dispiriting times they live in. They have their first extraordinary speaker in decades taking the oath of office. They know how good he’s been. Time for great.

How tall is the order?

“The great task of Barack Obama is to be a John F. Kennedy or to be a Ronald Reagan — truly inspire the American people and in a few succinct, memorable lines, lay out for the country your new vision for America,” says American University political historian Allan J. Lichtman.

Gulp.

At least that does not call upon Obama to be another Abraham Lincoln, the unsurpassed cosmic communicator whose words and deeds the president-elect often cites, and probably will again from the stage of the Capitol.

Obama can be expected to hit upon all lodestar themes from the canon of inaugural speeches. Some of them are unity, hope, change, continuity, security and God. (Prosperity, another biggie, may have to wait.)

The historic ascension of a black man to the White House begs for eloquent acknowledgment. Students of inaugural speeches expect that in brief. Just seeing Obama take the oath may say more on that subject than his rhetoric could.

One of the memorable characteristics of inaugural addresses is how forgettable most of them are.

Perhaps not since Reagan declared “government is not the solution to our problem, government IS the problem,” has a line with staying power come from an inaugural speech. Even that thought was only satisfying to the ideologically like-minded. But it showed the change Reagan wanted for his country.

“The number of really plodding speeches is almost countless,” says Leo Ribuffo, history professor at George Washington University. “The ones that stand out: maybe eight-nine if you’re a historian, maybe three or four if we just have a vague sense of the past.”

Count Lincoln, Franklin Roosevelt, Kennedy, Thomas Jefferson and one or two more as the acknowledged masters.

Jefferson’s first inauguration, in 1801, was the first that marked the transition between rival parties.

“We are all Republicans, we are all Federalists,” he said, reaching to erase bitterness between parties of the day.

We are not just red states or blue states but the United States, Obama says now. The sentiment is certain to be heard in his speech, if dressed in new words. Can Americans truly rally together behind such a call?

“Isn’t it pretty to think so?” Ribuffo muses. “The problem is, all presidents want to bring the country together on their own terms.

“I think Americans understand really that an inauguration is like a graduation or a wedding. There’s a kind of rhetoric of great optimism and then afterward, well maybe the graduate doesn’t get the greatest job in the world. Maybe the marriage is a little rocky. But today, at least, let’s look on the bright side.”

Lincoln’s second inaugural speech, coming with Civil War victory days away and his assassination the following month, made the transcendent appeal for national reconciliation, “with malice toward none, with charity for all.” It was a short speech, loaded with religious touchstones, and perhaps the greatest inaugural address of all.

But his unity was achieved by force of arms, not rhetoric.

Roosevelt embodied hope, change and the possibility of having security and even prosperity once again, speaking in 1933 to a nation in the roughest grips of the Depression.

Obama has spoken lately about how bad things are. He can be expected to address how good things can be again. He already has been invoking FDR, obliquely, in reminding Americans that previous generations have faced down war, depression and “fear itself.”

“We’re in a sour mood, we’re pessimistic,” said Stephen J. Wayne, government professor at Georgetown University. “The new president has to try to restore hope and confidence and try to restore the proposition that had been so valid for many years — that the future is going to be better than the present.”

FDR railed against the moneychangers in a speech delivered in the midst of a bank panic, with one-quarter of the work force idle. His words were angry and hopeful at once.

He advanced a thought that is foreign to the ears of the modern consumer — that the crisis concerned, “thank God, only material things.”

“Only a foolish optimist can deny the dark realities of the moment,” he said. “Yet our distress comes from no failure of substance. We are stricken by no plague of locusts.”

The fundamentals are strong, you might say.

Kennedy embodied hope, change, common purpose and of course the passing of the torch to a new generation.

Again, Obama is not waiting for Jan. 20 to draw on the magic of historic moments such as Kennedy’s turn on the inaugural stage in 1961.

He has asked Americans to “insist that the first question each of us asks isn’t ‘What’s good for me?’ but ‘What’s good for the country my children will inherit?”‘

Expect that thought to be expressed more poetically on Inauguration Day, in the spirit of Kennedy’s call: “Ask not what your country can do for you. Ask what you can do for your country.”