Thomas Maier: Kennedy's heritage was of an immigrant family that broke barriers
Maier says the Kennedy brothers pushed wider opening of U.S. borders in 1960s
He says resulting demographic change helped usher in President Obama's election
Maier: Like JFK, Obama's background is much different than other presidents
By Thomas Maier
Special to CNN
Editor's note: Thomas Maier is the author of "The Kennedys: America's Emerald Kings," (Basic Books), which was the basis of a Warner Bros. video documentary released in November. He is a reporter for Newsday.
(CNN) -- With a sign from Dunganstown, Ireland, hanging in his U.S. Capitol office, a reminder of the famine-ravished farm where his ancestors began, Sen. Edward "Ted" Kennedy always seemed to understand that the Kennedys were perhaps America's greatest immigrant story -- overcoming religious, ethnic and cultural barr…