That could leave Mr Zedillo overseeing the party's first presidential primaries with only one runner, his own.
The test of whether the front-runners can carry the momentum will come quickly, as the New Hampshire primaries are only five days away on January 8.
Primaries are not the only reason that candidates are running earlier.
Right now, you have a situation where if you look back at the play(ph) of the year 2000, you had only 10 primaries and caucuses by March 1st.
Only a few primaries and caucuses have been held so far this year, but questions are already being raised about the reliability of voting equipment.
Montana and South Dakota are completing the primaries, with Mr Obama only a few delegates short of the 2, 118 needed ahead of the polls closing.
But then there were only a handful of primaries stretched out between March and June.
After Iowa and New Hampshire, why not have only two or three primaries or caucuses a week?
Kerry's continued wins in the primaries, week after week, can only help his chances as the prospective nominee.
She said she would stand only when Kadima held its own primaries.
Registered party members can vote only in their own party's primaries, but independents can vote in either.
The late Vicente Saadi, Ramon's father, was the only Justicialist governor to back him in the party primaries for the 1989 presidential contest, and provided him with many of the political contacts that brought him eventually to the presidency.
The only thing that the evangelical leadership could agree on during the Republican primaries was that they wanted anyone but Mr McCain.
The only drawback is that general-election money cannot be used in the primaries.
And unlike New Hampshire and South Carolina, where McCain won primaries thanks to support from independent voters, Florida holds a closed primary, meaning only registered Republicans can vote in the GOP primary there.
Of the 21 primaries and caucuses held so far, Kerry has won 19, while Edwards has won only his native state of South Carolina.
In recent history, conventions are basically a meaningless tradition in which only one ballot is held, choosing a nominee that has already been decided in the primaries.
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Still, the Indiana Elections Commission expects Tuesday's turnout to be on par with levels seen in 1998, when only 24 percent of the state's eligible voters turned up for mid-term primaries.
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Even if only a fraction of them do, it could still be decisive in low-turn-out primaries.
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