Tuesday's primary victories in Ohio, Texas and Rhode Island gave Sen. Hillary Clinton, D-New York, about all her campaign could hope for: solid performances and a chance to close the delegate gap in the next primary, in Pennsylvania on April 22.

Still, the delegate math remains rough for the candidate seeking to become the first woman nominated for president by a major U.S. political party. Sen. Barack Obama, D-Illinois, leads in delegates, 1477-1391, including pledged superdelegates, according to a Washington Post tally, and the Clinton campaign's strategy will now be to try to close the delegate gap to 60 or so with a win in Pennsylvania. Two caucuses, Wyoming and Mississippi, occur before the Pennsylvania primary, and Sen. Obama is expected to win each and increase his delegate lead heading into Pennsylvania.

In 187-delegate Pennsylvania, the demographics favor Sen. Clinton -- she's leading in statewide polls there - - and the Clinton campaign likes its chances. Pennsylvania has a large working class -- which, along with women voters and Latin-Americans, forms the bulk of Clinton's base. If Sen. Clinton registers a solid win in Pennsylvania, she can make the case that although Sen. Obama has the delegate lead, she has won in the major states of New York, California, Texas, Ohio and Pennsylvania, and probably would have won in Florida, had the delegate count been included in the Democratic Party's nominating process. That big-state coalition, and the fact that she's the candidate of the working class, would be two strong philosophical points as the campaign attempts to secure pledges from the to-date 353 un-pledged superdelegates. (Note: The number of un-pledged delegates is likely to decline by the end of the primary season on June 3.)