Is Hillary Clinton's confidence slipping?

The New York senator sounded upbeat today as she took questions from a by-invitation-only roundtable discussion in Ohio, a state many political observers believe she must win to stay in the running for the Democratic nomination. She detailed her policy proposals for the mortgage crisis, for foreign policy, and for healthcare.

She talked about sending her husband, former President Bill Clinton, around the world on undetailed missions, and pointed out the success of her husband's trip to Indonesia with former President George H. W. Bush after the tsunami there.

But when asked about running a bipartisan White House, Clinton slipped.

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"We will bring into the United States government, if I'm your president, distinguished members of both parties,'' Clinton told the group at a Parma diner.

From the start of her campaign, Clinton has commonly said, "when I am president,'' suggesting she did not envision a scenario in which she might lose.

Clinton is favored to win March 4 in Ohio, where lower-income and labor union voters comprise a substantial part of the electorate. But recent polls show Clinton and Obama in a virtual tie in Texas, also considered a must-win state for her on March 4.