GREENSBORO, N.C. -- The historic action that four North Carolina college students took that led to desegregation at lunch counters more than half a century ago shows what young people can do to change their world for the better, first lady Michelle Obama said during a commencement speech Saturday.
Mrs. Obama addressed a crowd of about 15,000, including more than 1,200 graduates of North Carolina Agricultural and Technical State University, one of the state university system's historically black schools.
In 1960, four of the school's students put their careers and lives on the line by sitting down at a segregated Woolworth's lunch counter a few miles away, asked to be served coffee and were refused. They returned day after day in greater numbers, and others across the South followed their example, until the company eventually was forced to end separate treatment for black and white customers.
North Carolina is considered a battleground state in the presidential election and the first lady's visit was expected to generate goodwill within a core Democratic Party constituency as President Barack Obama seeks re-election this fall.
Mrs. Obama steered clear of references to politics and her husband's re-election bid, though the audience cheered when the first lady told graduates: "We have the responsibility to protect the ground that has already been won, because it can just as easily be lost."
President Obama has visited North Carolina more than a dozen times, including four since June. Most recently he blasted Republicans about student loan debt during a visit two weeks ago to the University of North Carolina of Chapel Hill. The Democratic National Convention will be in Charlotte this September.
Obama's likely Republican opponent for the White House, Mitt Romney, visited a Charlotte manufacturing plant on Friday to blame Obama for the slow pace of economic recovery. It was Romney's second visit to the city in a month.
Obama carried North Carolina over John McCain in 2008, with 95 percent of black voters supporting the Democratic nominee, according to exit polls. Whether they can deliver another win for Obama, as the state continues to grapple with unemployment rates that hover above the national average, remains to be seen.
North Carolina voters this week approved amending the state constitution to ban gay marriage. Obama followed the next day by becoming the first president to express support for same-sex marriage.
Mrs. Obama's Greensboro address was the second of three spring commencement addresses for the first lady. She spoke at Virginia Tech on Friday and also is scheduled to speak June 17 at Oregon State, where her brother, Craig Robinson, is the men's basketball coach.