Daniel Fromson writes at The Atlantic:
Although the U-S-A chant is often said to have originated with the 1980 "Miracle on Ice," in which the U.S. ice hockey team defeated the Soviet Union at the 1980 Winter Olympics in Lake Placid, New York, at least one incident of the cheer predates that famous game. David Litterer, co-author of The Encyclopedia of American Soccer History, points out that a U-S-A cheer occurred on October 26, 1979, when the U.S. men's soccer team traveled to Budapest and beat Hungary 2-0, "one of the most significant upsets in years."
Whatever the origins of the chant, the U.S. ice hockey team's championship run at the 1980 Winter Olympics made it a significant part of American culture. The chant first appeared when the United States faced Czechoslovakia, and it became a fixture during the team's remaining games—a perfect soundtrack to the triumph over the Soviets, a major symbolic victory for American patriotism.
When President Obama announced at about 11:30 p.m. Sunday that U.S. military agents had killed Osama bin Laden in Pakistan, a crowd gathered outside the White House -- largely composed of students from Washington-area colleges such as George Washington and American Universities -- erupted in cheers.
At the same time, students from Columbia and New York Universities and the City University of New York filled out the crowds at Ground Zero and Times Square in New York, and rallies popped up across the country at institutions such as the Universities of Michigan, Delaware, and Texas at Austin, and at Iowa State University.
Penn State University, Wake Forest University, the U.S. Military Academy, Radford University, and the State University of New York at Brockport were some of the other institutions that saw impromptu rallies. The crowds sang patriotic songs, waved American flags, and engaged in the type of revelry more commonly associated with football and basketball national championships. Many of the events drew hundreds of students -- far more than turn out for many scheduled and promoted campus events. Individuals also took to social media sites to join the crowds virtually, share news, and solicit views from other people.
The celebratory reaction among college students -- counter to the stereotypes of campuses as so far left-leaning that they are always anti-military -- raised questions about the current generation of college students and why so many reacted the way they did, and several experts on student behavior and attitudes were surprised by the spontaneous throngs. Many researchers point to 9/11 and say it had a broad impact on how young people view the world; others say it is the nature of the Millennial generation to want to gather at major historic moments. While there is no clear-cut answer, professors say there is a lot of room for further discussion.