Possible Kennedy successors

Andrew Card

Card, who served as President George W. Bush's chief of staff from 2001-2006, has said he will not join the race.

Strengths: From his years in the White House, Card can claim strong knowledge on the workings of Washington, especially between the White House and Congress.

Weaknesses: As a Republican and former Bush insider, Card faces an obvious uphill battle in heavily Democratic Massachusetts.

Card received an honorary doctor of public service degree at the University of Massachusetts Commencement in Amherst in May, 2007.

Andrew Card Card, who served as President George W. Bush's chief of staff from 2001-2006, has said he will not join the race. Strengths: From his years in the White House, Card can claim strong knowledge on the workings of Washington, especially between the White House and Congress. Weaknesses: As a Republican and former Bush insider, Card faces an obvious uphill battle in heavily Democratic Massachusetts. Card received an honorary doctor of public service degree at the University of Massachusetts Commencement in Amherst in May, 2007.
Michael Dwyer/AP