WASHINGTON  Senator Hillary Rodham Clinton needs three breaks to wrest the Democratic presidential nomination from Senator Barack Obama in the view of her advisers.

She has to defeat Mr. Obama soundly in Pennsylvania next month to buttress her argument that she holds an advantage in big general election states.

She needs to lead in the total popular vote after the primaries end in June.

And Mrs. Clinton is looking for some development to shake confidence in Mr. Obama so that superdelegates, Democratic Party leaders and elected officials who are free to decide which candidate to support overturn his lead among the pledged delegates from primaries and caucuses.

For Mrs. Clinton, all this has seemed something of a long shot since her defeats in February. But that shot seems to have grown a little longer.