President-elect Donald Trump at the Lincoln Memorial in Washington on Jan. 19, 2017. (Mike Segar/Reuters)

When Ulysses S. Grant gave his second inaugural address, he closed with an unusually grumbling note. From his time as a Civil War general to both of his campaigns, he said, “I have been the subject of abuse and slander scarcely ever equaled in political history, which I feel that I can afford to disregard in view of your verdict, which I gratefully accept as my vindication.”

Grant's final sentence was the sort of resentful retort rarely part of an inaugural address, a speech almost always enveloped in tradition, magnanimity and unifying calls to democratic values. Yet it's a reminder that ego can creep in to this most democratic of speeches — even if it shouldn't. “It's a mistake, no matter how much you resent it,” says Karlyn Campbell, a professor at the University of Minnesota who studies political rhetoric.

Whether such language is included in Donald Trump's inaugural address — an incoming president who tweeted about his “enemies” on New Year's Eve and has continued to jab and taunt his former opponent long after the campaign ended — is one thing scholars who study presidential speeches will be looking for as he takes the oath of office Friday and delivers his first remarks as the 45th president of the United States.

In addition to whether Trump shows humility in the speech, scholars said they will be looking for two other key elements: expressions of core American values made to unite a deeply divided electorate — even if delivered in platitudes — and a recognition that the power of the office comes from the Constitution. The inauguration, says Elvin Lim, a professor at the National University of Singapore and author of the book “The Anti-Intellectual Presidency,” is “a civics lesson that must be rehearsed, especially by the person who's about to take office.”

The central role of the inauguration address is to unite people after a divisive election, which presidents do by making appeals to core American values such as liberty, opportunity and equality. Sometimes this is done in soaring, eloquent language: “Let the word go forth from this time and place, to friend and foe alike, that the torch has been passed to a new generation of Americans — born in this century, tempered by war, disciplined by a hard and bitter peace, proud of our ancient heritage — and unwilling to witness or permit the slow undoing of those human rights to which this nation has always been committed,” John F. Kennedy said in his famous inaugural address.

Sometimes it is more plain-spoken: “I have no new dream to set forth today, but rather urge a fresh faith in the old dream,” Jimmy Carter said in his own speech.

It doesn't matter too much, Lim says. The inaugural address “is the one place where it's okay to be simple and be full of platitudes, because that's actually what ceremonial speeches are supposed to be,” he says. “This is really about rehearsing our values.”

In some sense, taking the oath of office is only part of becoming president, says Kathleen Hall Jamieson, a professor who studies presidential rhetoric at the University of Pennsylvania. “You swear the oath and you start speaking, but you become the president rhetorically by delivering the inaugural address.”

Campbell agrees. “The oath the president takes is inadequate without the speech that follows,” she says. “The president has to say the kinds of things that make you say, 'Oh yes, it's right. You've taken the oath, you have plans as a president that I can affirm, you understand the values of the country.' "

If Trump doesn't do that, she says, the speech loses the “real function of the inaugural address,” which is to bring people together around common beliefs. “If it doesn't perform that function, then all of the disagreements and conflict get pushed forward.”

She points to George W. Bush's inaugural address, given after a lengthy battle over the election results that went all the way to the Supreme Court. Although he thanked Al Gore “for a contest conducted with spirit and ended with grace,” Campbell says, Bush “never acknowledges in the inaugural what has happened” with the protracted election fight, and that it is not until after Bush speaks following the Sept. 11, 2001, terrorist attack that he seems to unify the country as president.

Lim says the inaugural address is also an opportunity to affirm that the power of the office of the president is granted through the Constitution. “This is a very modern thing — all presidents now think their power comes directly from the people,” he says. “But if you read the oath, the oath is to the Constitution. It is an office, it is an institution.”

He says early inaugural addresses, particularly those by Jefferson and Washington, exercised restraint when talking about the power they were invested in. “In any democracy, power needs to be exercised and obtained,” Lim says. “It's one of those credo elements that should be in any inaugural address.”

Trump, of course, strode to an electoral college victory on the polar opposite of restraint, running a campaign of charisma, bravado and brashness that shattered political norm after political norm. And so, Lim and others say his inaugural address may very well not sound those notes.

“It's not in his bones to speak like a small 'r' republican,” Lim says of Trump. “The best thing he could do is to simply use the speech to do all the boring and traditional things.”

Campbell, too, says she'll be looking “for some signs of humility,” as well as “some kind of indicator of what his plans are for the future that are connected to basic American values.” But a swaggering inaugural address may not be the worst outcome. “The worst thing that could happen in an inaugural is to have it be divisive,” she says. “That means the whole process isn't possible of reuniting the nation after the election.”

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