Andrew, who was appointed DNC chairman by former President Bill Clinton and served from 1999 to 2002, originally endorsed Sen. Clinton, citing her “experience” and ability to “compete and win.”

But in an open letter to Democrats, he explained his change of heart by arguing that the increasingly heated race between the two contenders is not only hurting the party, but also helping the presumptive GOP nominee, Sen. John McCain. “It is clear that a vote for Hillary Clinton is a vote to continue this process,” he wrote, “and a vote to continue this process is a vote that assists John McCain.”

In last night’s “Nightline” interview, Clinton said she had not spoken to Andrew, and defended a possible fight to the finish between her and Obama.

“Anyone who believes this is bad for the party I just think is not paying attention,” she said, “because the level of enthusiasm to be part of this process is, from my perspective, helping us build a stronger and deeper Democratic base.”

Talk of the latest defection was limited during a Clinton camp conference call yesterday afternoon. Instead, the focus was new math–in the form of polls–citing stronger support from young voters and independents for Clinton in head-to-head matchups against McCain. Geoff Garin, Clinton’s new chief strategist, also furthered the argument that Clinton can beat McCain in crucial swing states like Ohio and Florida, where the latest poll shows Clinton leading Obama versus McCain by substantial margins. “It’s very hard to think of the electoral math that leads to a Democratic victory without Ohio and/or Florida and Senator Clinton clearly appears to be in much stronger shape in those states,” Garin told reporters on the call.

The Quinnipiac poll Garin refers to puts Clinton ahead of McCain by 10 points in Ohio and eight points in Florida. McCain leads Obama by one point in each state. Technically, it sounds like good news for the Senator, but the two states will not be in play until the general election and anything can happen between now and then. Howard Wolfson, Clinton’s communications director, acknowledged that the polls could be “ephemeral.” “What I don’t think is ephemeral is the place where we’ve landed in terms of the economy and the place where we’ve landed in terms of the candidate who is far more successful at keeping blue collar and middle income voters in the Democratic column.”

In spite of Clinton’s connection to such voters–and a gain of six superdelegates since the last primary–Obama, with 11, has still outpaced her in the post-Pennsylvania battle for the support of these all-important party activists and elected officials. And now Clinton faces a new challenge in Andrew’s call to other super delegates to–in effect–count her out and coalesce around her opponent.

But in her Nightline interview, Clinton wasted no time in reaffirming a call of her own. “I think that this is such a close election, why would any of us think that it shouldn’t go to the end? We’ve got a process. The rules are it goes all the way into June. Let’s follow the rules and get to those June contests and see where are.” Until June it is.