For Democratic candidates, the decisive factors in Iowa and New Hampshire are personal and tactical; for GOP contestants, however, the ultimate outcome may be decided by the relative strength of newly combative ideological elements.
From holiday distractions to winter weather, the people who will be measuring voters' preferences in primaries and caucuses around the nation will be dealing with unprecedented problems. Here's how they plan to do it.
Awareness of Winfrey's support for Obama was equally high across parties, genders and racial groups; leading GOP candidates still lag behind Obama and Clinton in public visibility.
Voters, especially Democrats, in two early primary states are being inundated with phone calls, mail and other campaign contacts; but so far there are few signs of campaign fatigue.
Likely Republican voters in the three politically disparate early primary states express less enthusiasm about their field of presidential candidates, and many voice only modest support for their choices.
Democrats enter the presidential primary campaign upbeat about their candidates and united in their views on major issues. Sen. Hillary Clinton is the Democratic frontrunner in three key early primary states, holding a slim five-point edge in Iowa and more substantial 19-point and 14-point leads in New Hampshire and South Carolina, respectively.
A look at the attitudes of the regular buyers and sellers who make the stock market go up and down finds they are, among other things, even more likely to support the frontrunners in both the Democratic and Republican primaries.
A survey finds no evidence that a significant number of voters are considering crossing party lines -- or voting strategically for the other party's weakest candidate.
A year before the 2008 presidential election, most major national opinion trends decidedly favor the Democrats and discontent with the state of the nation is markedly greater than it was four years ago. Also, Republicans have become less likely to say that their party is doing a good job standing up for its traditional positions.
Many more Republicans are able to recall unprompted the names of Democratic frontrunners Hillary Clinton and Barack Obama than can name Rudy Giuliani and other leading GOP candidates.