State parties have been planning for months just in case races didn't get decided Tuesday.
With so many candidates in the Senate and three House races, there was a chance no one would win primary night with a minimum 35-percent threshold.
In the 3rd Congressional District that's exactly what happened.
Brad Zaun led the way with 28-percent of the vote but at the convention, all five candidates will start with a clean slate.
The GOP last held one in 2002.
Attention will now turn from mailings to the delegates.
“It will be like the caucuses on steroids except even worse because everyone knows exactly who the voters will be,” West Des Moines voter and delegate John Stineman said.
A time or place for a third district convention hasn't yet been confirmed.