U.S. President John F. Kennedy delivers his inaugural address after taking the oath of office at Capitol Hill in Washington, D.C., on Jan. 20, 1961. Kennedy said, "we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe, to assure the survival and success of liberty." Kennedy was sworn in as the 35th president of the United States. (AP Photo)

Inaugural speeches tend to be remembered for their soaring rhetoric aimed at bringing the country together. And indeed, this is their primary purpose: From Thomas Jefferson’s first (“we are all Republicans, we are all Federalists”) to John F. Kennedy’s address (“ask not what your country can do for you …”) to Abraham Lincoln’s second (“with malice toward none, with charity for all … let us strive on to finish the work we are in, to bind up the nation's wounds”) the most memorable lines are directed at Americans' need for unity after divisive and hard-fought elections.

But there is another audience for the inaugural speech that often gets less attention: The broader world. Unlike the State of the Union address, which is often a laundry list of legislative priorities, or a farewell address — an opportunity to reflect, recap and in some cases, issue warnings — presidents have often used their inaugural addresses to send a signal or direct a message to the wider world about the coming presidency. In augural speeches, "there is always going to be a broad vision of American foreign policy, a broad statement that’s going to be there because there is that international audience," says Elvin Lim, a professor at the National University of Singapore who has written about presidential speeches.

People often forget this, says Kathleen Hall Jamieson, a professor at the University of Pennsylvania’s Annenberg School of Communication who studies presidential rhetoric. “With the State of the Union address, even though the world is eavesdropping, you’re really proposing legislation, the focus is on the Congress,” she says. “The world is envisioned differently in inaugurals than in other speeches. The only other time the world is invited into the speech, writ large, is when the president makes an invitation to Congress to declare war.”

She points to lines from several famous inaugurals as examples. Even though Woodrow Wilson had campaigned with the slogan "he kept us out of war," during his March 1917 second inaugural he memorably declared "we are provincials no longer. The tragic events of the thirty months of vital turmoil through which we have just passed have made us citizens of the world. There can be no turning back. Our own fortunes as a nation are involved whether we would have it so or not."

Almost exactly a month later, he asked Congress for a declaration of war on Germany. "It's an acknowledgement that a person first elected on one set of assumptions is now drawn into a different world," Jamieson says.

John F. Kennedy's inaugural address is best remembered for his "ask not" line, but just as important was his commitment that the United States "shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and the success of liberty."

In his book about Kennedy's speech, author and historian Thurston Clarke writes that the famous sentence "was a warning to the Kremlin hard-liners that the youngest man elected president would not be bullied." But in hindsight, Jamieson says, "we look back on it very differently. We look at that now in the context of Vietnam."

There are others, of course. Franklin Delano Roosevelt said in his third inaugural that "the task of the people is to save that Nation and its institutions from disruption from without." George H.W. Bush directly addressed other nations, saying "to the world, too, we offer new engagement and a renewed vow: We will stay strong to protect the peace. The offered hand is a reluctant fist; once made -- strong, and can be used with great effect."

It was a line President Obama would echo in his first inaugural ("we will extend a hand if you are willing to unclench your fist") just after the short but controversial paragraph he addressed "to the Muslim world," saying "we seek a new way forward, based on mutual interest and mutual respect."

How much President-elect Donald Trump will speak to the outside world is of course, unknown. Reports have said he's looking to inaugural addresses by Ronald Reagan and Kennedy for inspiration. Presidential historian Douglas Brinkley told CNN Trump said he wants to write the speech himself and wants it to be short. On Wednesday, he tweeted a picture of himself at the "Winter White House," his Mar-a-Lago resort in Florida, saying it was of him writing a draft of the speech.

Trump's inaugural comes at the end of a week when he shocked European leaders after remarks in an interview with the Times of London and the German newspaper Bild. In it, he called the European Union "basically a vehicle for Germany," as well as reiterating that NATO is "obsolete" while saying the defense alliance "is very important to me."

Jamieson says that while many presidents have used the speeches to send signals about foreign affairs to the world, they've also typically done so carefully. "What inaugurals are not supposed to do is provoke controversy," she says. On Friday, of course, the world will be watching to see if Trump sparks any.

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