(CNN) – Seven former Democratic National Committee chairs who support Hillary Clinton’s presidential bid, and the family of one who is deceased, released a letter Friday arguing that she is the candidate best-equipped to beat John McCain in November.

The letter was signed by former party leaders Kenneth Curtis, Charles Manatt, Debra DeLee, Don Fowler, Steve Grossman, Pennsylvania Governor Edward Rendell, and Clinton adviser Terry McAuliffe. It was also signed by the family of the late Ron Brown, who served in the Clinton administration.

They write that “if the election were held today, Hillary would beat Senator McCain, but Senator Obama would lose to the presumptive GOP nominee.”

“Hillary has run one of the most formidable campaigns in the history of our Party,” the chairs wrote, listing Clinton’s primary season victories. “Her base of support includes women, Hispanics, seniors, Catholics, middle and low income Americans, and rural, suburban and urban voters. That’s a formidable coalition tailor-made for victory in a November general election.

“…We encourage you to continue to fully consider Hillary Clinton and the fact that she is qualified and accomplished. Too much is at stake for us not to consider deeply the choice we must make for our Party and our country.”

The letter comes hours after Barack Obama’s campaign announced the endorsement of Paul Kirk, the second former DNC chair to endorse his presidential bid in two days. Kirk had been described as an Obama supporter in some campaign reports, but had not publicly stated his endorsement of the Illinois senator.