One has to wonder if it is an open or closed primary.
Second, why is Kerry always the "presumed", "assumed", or "presumptive" nominee? He already has the nomination locked up. I just find it funny that even though Kerry has won the nomination, it is implied that he might not get it.
Finally, if one checks every election, between 5% and 10% of a candidate's party will not vote for their nominee. These people are the ones who almost always have a protest vote, Republicans tend to vote for the Constitution Party while Democrats vote for the Watermelon (Green) Party.
"There is no victory at bargain basement prices."