FILE - In this Oct. 13, 1988, file photo Democratic presidential candidate, Massachusetts Gov. Michael Dukakis, acknowledges the auditorium as Republican presidential candidate, Vice President George Bush, looks on after their final debate in Los Angeles, Calif. Dukakis says that while the rapid spread of negative information online poses new challenges for candidates, every generation of politicians has to learn the necessity of effectively countering attacks. "The worst mistake of my political career, and it was a colossal failure, was that I was not going to respond to the Bush attack campaign," he says. (AP Photo/Lennox McLendon, File)