Sen. John McCain jumped to a commanding lead in the Republican delegate race over Mitt Romney on Super Tuesday. Senators Barack Obama and Hillary Rodham Clinton were in a close race for Democratic delegates.
Mr McCain won 227 delegates to 36 for Romney and 24 for former Arkansas Governor Mike Huckabee. A total of 1,023 delegates are up for grabs in 21 states.
Overall, Mr McCain led with 331 delegates, to 129 for Mr Romney and 69 for Mr Huckabee. It takes 1,191 to win the nomination at this summer's convention in St Paul, Minnesota.
Mrs Clinton won 64 delegates in early voting, while Mr Obama captured 57. A total of 1,681 delegates are at stake in 22 states and American Samoa.
Overall, that gave Mrs Clinton 325 delegates, to 259 for Mr Obama, with 2,025 delegates required to claim the nomination in Denver at this summer's convention.
The Associated Press tracks the delegate races by projecting the number of national convention delegates won by candidates in each presidential primary or caucus, based on state and national party rules, and by interviewing unpledged delegates to obtain their preferences.
In some states, like Iowa and Nevada, local precinct caucuses are the first stage in the allocation process. The AP uses preferences expressed in those caucuses to project the number of national convention delegates each candidate will have when they are chosen at county, congressional district or state conventions.