Let me associate myself with Randy Turner’s thoughts on the 2008 GOP primary. Steelman hurt Hulshof more in the general by her awkward endorsement than by anything she said or did in the primary. Hulshof was a bad candidate barely able to beat someone in the primary even with the support of the entire GOP establishment, and he didn’t stand much of a chance in the general with or without a primary challenger.
And let me say that primary challenges are on the whole good for a party, not bad. The long battle between Obama and Clinton made Obama better able to take on McCain, a spirited fight in the VA Senate primary in 2006 gave Jim Webb the boost the Democrats needed to win the Senate in 2006, and so on. As long as two sides can come together to work for the greater good after the primary is over, a hard-fought primary is not a bad thing.