Party insiders don't like primaries. Suprising things happen on election day because the most conservative members of the GOP tend to turn out in droves when they haven't registered in the polls previously. In 1996, Illinois Lt. Governor Bob Kustra, a mushy moderate, was 20 points ahead and considered a shoo-in for the Senate nomination. He went to bed happy on primary night and awoke to discover some unknown state rep. named Al Salvi had beaten him (as this article shows)
The establishment FEARS Simon and O'Malley. Simon could pull off another Michael Huffington in California, only this time...he has a good shot at winning the general too!