The complaint one usually hears is that open presidential primaries in states Republicans will never carry give an advantage to more moderate or liberal Republicans. There's something to be said for that theory. It's also a variant of the Carter-Clinton-era complaint of liberal Democrats that the Super Tuesday primaries in Southern that Democrats usually lost hurt the more liberal contenders who were the choice of party activists.
Open primaries were a good idea when the parties weren't so ideologically divided. If there was a chance that Democrats might actually nominate the more conservative candidate, it was a good idea to be free to help that candidate win his primary. That rationale doesn't exist nowadays, but if one party's primary were confined to paid-up dues-paying members of a political party, the candidates chosen wouldn't be as representative of the constituency as a whole and would be likely to lose the general election.
“Open primaries were a good idea when the parties weren’t so ideologically divided.”
That is well stated and has been my understanding as well. I really don’t see the advantage of open primaries the more vituperative and divided our politics have become.
Mississisppi is facing thie dilemma right now. While the nation is focused on the McDaniel tea party Senate challenge to Thad Cochran, the Palazzi House race has become interesting since one-time democrat and previous office holder, now turned republican, Gene Taylor, has entered the republican primary against Palazzi.
http://yallpolitics.com/index.php/yp/post/37203/