Hillary Clinton is turning her attack on Barack Obama toward his electability, saying she is in a better position to be competitive against presumptive GOP nominee John McCain and making a concerted effort to not deny reports that she told a prominent Obama backer he simply can't win a general election.

In an afternoon press conference in California, Clinton at first seemed to deny a story, which initially appeared on ABCNews.com, that said Clinton told Bill Richardson -- a former presidential candidate and Clinton administration official -- that "(Obama) cannot win, Bill. He cannot win."

Asked whether she said that, Clinton answered Thursday: "You know, we have been going back and forth in this campaign a lot, who said what to whom. ... I don't talk about private conversations, but I have consistently made the case that I can win because I believe I can win and, you know, sometimes people draw the conclusion I'm saying that somebody else can't win," Clinton said.

"So that's a no?" the reporter asked.

"That's a no," Clinton said.

But the Clinton campaign now claims she misheard the question, after articles reported that the New York senator denied the Richardson conversation.

Spokesman Mo Elleithee said Clinton was trying to say, "no," she wouldn't talk about the conversation. He said it was not an outright denial that the conversation took place.

That seems to align with the approach Clinton's advisers took earlier in the day.

On a conference call earlier, Clinton's advisers also would not confirm or deny the alleged conversation, leaving the door open on how hard she's pushing the electability argument. Instead, senior strategist Mark Penn told reporters that the campaign's message is simply that Clinton is better equipped to beat McCain, and not that Obama is unable to win.

Campaign advisers said Thursday that surveys, exit polls and demographic trends show Clinton outperforms with Hispanics, Reagan Democrats and women.

"We have consistently made a case that Senator Clinton is more electable than Senator Obama," Penn said. "We see this... in the level of the constituencies that she has been attracting. She has been doing extremely well with working-class voters, Catholic voters, women voters, Latino voters."

The latest Gallup poll released Thursday shows that Democrats remain divided in their preference for a presidential nominee. According to the poll, 49 percent support Obama and 46 percent back Clinton. The poll also found Obama and Clinton about even with McCain when it comes electability in the general election. McCain beats Obama 46-45 and beats Clinton 47-45.

Expressing confidence that the former first lady will win Pennsylvania's April 22 primary despite her shrinking lead, officials said Clinton has triumphed in the largest, most important states even though Obama leads in pledged delegates overall.

In the press conference with reporters on Thursday, Clinton stressed the importance of winning Pennsylvania, saying, "It's a state that Democrats have to win. You can't get to Pennsylvania Avenue if you don't win Pennsylvania."

Campaign strategists said they hope their electability argument will resonate among the more than 300 superdelegates who have yet to offer a commitment to either candidate.

But Obama is catching up to Clinton in superdelegates, with 220 to her 250. One Clinton superdelegate, New Jersey Gov. John Corzine, said he might change his vote to Obama if the Illinois senator continues to lead by the end of the primaries. Corzine said Clinton will need a big win in Pennsylvania in order to remain viable in the race.

"I think she needs a good, big win,'' Corzine said in an interview aired Thursday on CNBC. "You have to see a real cut into this popular vote, and I think she's going to get it.''

Clinton Communications Director Howard Wolfson dismissed Corzine's remarks, telling reporters on Thursday that "a lot is going to happen between now and the end of the primary period. One thing you can anticipate in this race is that the unanticipated will happen. ...We believe we are going to make the case that we need to make that Senator Clinton is ready to be commander in chief."

FOX News' Aaron Bruns contributed to this report.