WASHINGTON --- When it comes to presidential primaries, Democrats and Republicans play by different rules.
One party likes to share. The other, not so much.
That goes a long way toward explaining why Arizona Sen. John McCain hopes to take control of the race for the Republican presidential nomination in Super Tuesday's primaries and caucuses.
And why the busiest primary day in history might merely intensify the contest between Democratic rivals Hillary Rodham Clinton and Barack Obama.
In all, Democrats have primaries in 15 states and caucuses in seven states and American Samoa on Tuesday, with 1,681 delegates at stake.
Republicans hold 15 primaries, five caucuses and one state convention, and pick 1,023 delegates.
Nine of the Republican contests are winner-take-all.
Mr. McCain is favored in primaries in five of them -- his home state of Arizona, in addition to Rudy Giuliani's New York, and New Jersey, Connecticut and Delaware. That's a total of 251 delegates. Mr. Romney is the favorite in the primary in Utah.