As Americans queued up at polling stations across the nation, leading Democratic contenders Barack Obama and Hillary Clinton fought a see-saw battle while the main Republican frontrunner John McCain sought to bury his rivals at the Super Tuesday primaries, a 24-state showdown.
With each party holding primaries or caucasus in more than 20 states, including some of the most populous like New York, the single-day voting will account for over half the delegates who go to party conventions to formally choose the nominees to run in November's presidential election.
Hillary Clinton, who was long seen as the main contender among the Democrats, has seen her lead in polls disappearing to almost nothing in just a matter of weeks as first-term Senator Barack Obama wins over voters with his refreshing theme of hope and change.
With neither candidate expected to come out the clear winner after the Super Tuesday votes, the Senators have spent millions of dollars on campaigning and advertisement blitzes across the vast country in an effort to edge ahead.
Numbers-wise, the Democrats have more at stake than Republicans on Tuesday where they hold 15 primaries and seven states caucuses plus American Samoa, with 1,681 delegates for the national party convention up for grabs.
