As an example of what she called "manipulation," Orrock referred to the controversy at the Republican convention in 2012, in which backers of nominee Mitt Romney raised the bar for how candidates could qualify on the convention ballot, in order to avoid any symbolic floor votes for Ron Paul.
While Romney's nomination four years ago was never in doubt, this year, it could go down to the wire. A brokered convention, in which it takes more than one round of delegate voting to choose the nominee, appears likely, said Orrock. "That's just realistic."
Democrats experienced the last truly brokered convention in 1952. Republicans came close at their 1976 convention.
For Trump to lay claim to the 2016 nomination coming into the convention, he needs to win 1,237 delegates. He's more than halfway there ahead of Tuesday's winner-take-all Arizona primary. Utah also holds caucuses. But with Texas Sen. Ted Cruz and Ohio Gov. John Kasich still in the race, they might be able to win enough delegates to deny Trump the magic number.
"There's been attempts from all sides to take Donald Trump out of the mix. And it hasn't been very successful. The more they attack him the stronger he gets. And he's resonating with America and the voters," Orrock said.