"Gov. Branstad certainly won't be the person determining if there's a straw poll," Spiker told The Hill.
“It has been a great fundraiser for the party but I think its days are over," he said.
The straw poll has for 33 years been a must-attend for Republican presidential contenders, as an opportunity for candidates to fundraise and test-run their campaign organizations.
It's also traditionally been viewed as a trial-run for the Iowa caucuses the following year -- a perception that has been called into question in recent years by the straw poll's poor track record at predicting eventual caucus winners.
Spiker said that the Iowa GOP state central committee would decide in 2015 whether the straw poll would prevail, but that it was very popular with current members.
"It is a very, very helpful organizational tool," he said.
Spiker also disputed arguments that Bachmann's loss indicates the poll is no longer relevant, because, he said, she never created the infrastructure in Iowa to ultimately win the caucus. But he added that the purpose of the straw poll may be misperceived.
"It certainly wouldn't make or break somebody as a candidate," he said.