We come from different backgrounds, parties and pursuits but are bound by a common belief in the promise and purpose of America. After all, each of us has been the beneficiary of the choices made—and opportunities created—by previous generations of Americans.

One of us grew up poor in the South Bronx of the 1960s and went on to lead a children's antipoverty program in Harlem. Another grew up in a small town in South Jersey, and went on to be a leading money manager. The third grew up in a small suburb in upstate New York and...