Jon Stewart hosted a panel discussion on the Daily Show on Wednesday discussing this question of potential Democratic pitfalls going into November. This is an important issue to think about because any Democrats who think winning any of these senate seats simply because the nominee seems like a wacky extremist are badly misreading the current political and media climate. The two major ways the Democrats could miss this opportunity, which were not directly addressed in Stewart's forum, are by assuming the voters all know how extreme the Republican Party candidates are in these races, and ignoring how some Democratic candidates, and thus the party more generally, will be portrayed by the Republicans.
The Democratic Party in New York, because it really is almost everything to almost everybody, has no ability to enforce party discipline in the senate, or to defeat candidates who do not represent the views of the party. Excessive ideological rigidity is not a great situation either, but without some discipline, parties are almost meaningless.