Some 10 days ago, U.S. president-elect Barack Obama and his family made an impromptu visit to Abraham Lincoln's memorial.

The significance of the location, which honours the American president credited with ending slavery in the U.S., wasn't lost on the Obama girls.

Recalling the visit, Obama told CNN that seven-year-old Sasha read an engraving of Lincoln's second inaugural address and noted it seemed a bit too long.

"I said, 'Actually, that one's pretty short. Mine may even be a little longer," Obama said.

"At which point, Malia turns to me and says, 'first African-American president? Better be good.'"

Indeed, Malia isn't the only one putting pressure on the incoming president to deliver a speech that will resonate in the U.S., globally, and through history.

"(Tuesday's) speech will be a very important one, one that's watched by the whole world. It will set the tone in a time of crisis. Generally when a president is sworn in bad times, those are the speeches that get the most attention," says David Frum, the Canadian-born speechwriter credited with helping formulate the notorious "axis of evil" phrase in President George Bush's 2002 State of the Union address.

Political strategist Peter Fenn, whose communications company has worked on Democratic campaigns going back to the 1980s, says the expectations for Obama's inaugural speech couldn't be higher.

"I think people are going to look for very much what (John) Kennedy gave them in 1961. They are going to look for a rhetorical flourishing -- and look for inspiration," Fenn says.

"I think you'll find this speech, like all his speeches, very strong in theme and message. He's going to talk a great deal about personal responsibility, about the country binding together, (and) about how we have serious problems we've got to solve together."

Obama has hinted at the broad tone his speech may take, telling ABC News he wants it to capture the "moment we are in." The newly elected president laid the groundwork for high expectations in 2004 when he mesmerized the audience at the 2004 Democratic convention.

The speech's call for a united America not tethered by partisanship catapulted the virtually unknown local politician into a national spotlight that hasn't dimmed since. His speeches during this year's primary season, particularly after the Iowa caucuses, were pivotal to his success.

But critics have also feared Obama's rhetoric may be merely that -- words without substance.

Frum, the one time White House insider, warned his former boss's successor not to overreach during Tuesday's inauguration.

"The Kennedy speech was no favour to the people who came afterwards because it was so soaring and grandiloquent," Frum says.

That speech set the U.S. on a new course, and is, perhaps, best known for the line, "Ask not what your country can do for you -- ask what you can do for your country."

Frum cautions that "had things turned out a little differently, had Kennedy lived to a ripe old speech, that speech may seem a little ridiculous in that respect. It acquires its power from his life story."

Frum and Fenn both say they haven't seen so much excitement about an incoming presidency for decades. Noting the historic nature of the Obama inauguration, Frum had one more tip for the new president.

"The drama of the moment will speak for itself," he said.

"Speak to your time. Tell people what you're going to do."