In the lead up to the crucial Pennsylvania vote, Barack Obama has secured more key endorsements, in a further blow to the Hillary Clinton campaign.
Former Senators, Sam Nunn and David Boren have formally endorsed Obama, in addition to Robert Reich, the former Labor Secretary in the Bill Clinton administration.
Nunn was a former Senate Armed Services Committee Chairman from Georgia. Boren of Oklahoma an Oklahoman was chairman of the Senate Intelligence Committee.
Reich's endorsement for Obama will be a major disappointment for the Clinton camp - the second high profile former member of the Clinton administration to back Obama. Bill Richardson's endorsement of Obama last month is still grating on the Clinton team.
Obama secures Key Endorsements
