Business Times - 24 Apr 2008 When will the US presidential race really begin? By LEON HADAR WASHINGTON CORRESPONDENT SENATOR Hillary Clinton has won the Democratic presidential primary in Pennsylvania - a crucial 'swing' state in the general presidential election - on Tuesday. Apparently, the margin of victory over her rival, Senator Barack Obama, about 10 per cent, is a number that seemed to have played well in the media-driven game of expectations. Indeed, most pundits had argued on the eve of the primary that Mrs Clinton would need to win by more than 8 per cent in order to gain the momentum she needed in order to continue in her fight for her party's presidential nomination. And she did very well among important demographic groups: women, blue collar workers, Catholics, Jews and older voters. Mrs Clinton achieved her victory in Pennsylvania after facing a younger and more charismatic figure who had enough resources to outspend her during the month-long campaign in a sta