But leading in Iowa doesn't mean winning in Iowa, because the caucuses are bizarre:
Democratic candidates must receive at least 15 percent of the votes in that precinct to move on to the county convention. If a candidate receives less than 15 percent of the votes, supporters of non-viable candidates have the option to join a viable candidate group, join another non-viable candidate group to become viable, join other groups to form an uncommitted group or chose to go nowhere and not be counted. Non-viable groups have up to 30 minutes to realign.In a regular primary, they'd just vote and be done with it. But in Iowa, only a few hard-core voters will show up for the long, grueling process--in '04, it was just 6% of registered voters. So the first step is getting your voters there. This is why the three front-runners are spending so much time and energy in Iowa--to create enough energy that their supporters will show up on caucus night (as Dean's, famously, failed to do). This is why it's difficult to look at polling numbers and figure out which candidate is actually doing well among the six percent who will actually show up.
Okay, so now the voters are at their precincts. Let the horse-trading begin! Here is another bump in the road for Hillary--she will easily hit the 15% mark, as will Edwards and Obama in most precincts. But what happens to the left-overs? If Hillary is looking strong, it's possible that the anti-Hillary forces (of which there are far more) could choose to band together. In some ways, the issue isn't how much support Hillary has going in, but how much those who are in other camps actually inhabit the anti-Hillary vote. In which case, they might throw their support behind the strongest candidate not named Clinton.