[cnn-photo-caption image= http://i.cdn.turner.com/cnn/2008/images/05/12/art.edwards.gi.jpg caption="Edwards says Clinton needs to be careful."]
(CNN) - John Edwards still says he is remaining neutral in the Democratic presidential race, but the onetime candidate all but said Sunday it is impossible for Hillary Clinton win the Democratic nomination, and warned the New York senator not to damage the party in the primary campaign's final stretch.
Appearing on CBS' Face the Nation, Edwards said Clinton has to be “has to be really careful that she’s not damaging our prospects," with continuing to take jabs at Obama.
"She doesn't need my advice, she knows this full well," Edwards said. "If she makes the case for herself, which she's completely entitled to do, she has to be really careful that she's not damaging our prospects, the Democratic Party, and our cause, for the fall."
Edwards also praised Clinton for the "strength and fortitude she has shown."
"I know how hard it is to get up and go out there every day, speak to the media, speak to crowds, when people are urging you to get out of the race. I mean, it's a very hard place to be in," he said. “But she's shown a lot of strength about that."
But the former North Carolina senator all but said her chances for winning the White House are over.
"The math is very, very hard for her," he said regarding her deficit in delegates to Obama. "The problem is, I think, you can no longer make a compelling case for the math.”
According to CNN's latest estimate, Clinton and Obama are now dead even in superdelegate support and Obama holds an overall 167-delegate lead.
Asked directly if Clinton should quit her White House bids, Edwards said, "I think it's a judgment that she has to make. And I think she's in a very, very tough place.”