In remarks at the White House, where he signed the U.N. Convention on the Rights of Persons with Disabilities, Obama said the ADA resulted from a movement carried out by people who "refused to accept a second-class status in America."
"It began when they not only refused to accept the way the world saw them, but also the way they had seen themselves," he said.
Obama praised several officials who helped get the ADA enacted, including Sen. Tom Harkin, D-Iowa, former Sen. Bob Dole, R-Kan., former Sen. Elizabeth Dole, R-N.C., and former U.S. Attorney General Richard Thornburgh.
Former President George H.W. Bush signed the ADA into law July 26, 1990.
Obama began the signing ceremony with praise for U.S. Secretary of State Hillary Clinton, who recently returned from an overseas trip that took her to, among other places, India.
"She is doing an unbelievable job," Obama said. "She's traveling all around the world delivering a message that America is back and ready to lead. And everywhere she goes she is representing us with grace and strength, and we are very fortunate to have her."
'How to Train Your Dragon 2' releases 5-minute clip
Yosemite climber falls 30 feet, suffers major injuries