Longtime U.S. Sen. Chuck Grassley, of Iowa, said Tuesday that the caucuses will not cull the presidential field "like we normally do."

The culling will not happen, he predicted, until after Jan. 21 South Carolina vote.

"Normally, you would have a winnowing process but there are so many free debates between now and South Carolina that I think until those free debates are over and or people run out of money," the field will stay large, he said.

Grassley said he expected former Mass. Gov. Mitt Romney to take the top spot in the Tuesday Iowa caucuses and Texas Gov. Ron Paul and former Pa. Sen. Rick Santorum to battle for second spot.

"I think you are going to have three winners," he said. "I think there is going to be one person that is one of two percentage points ahead."

He said the topsy turvey nature of Republicans preferences had several causes: people were waiting around for the "perfect candidate" and the candidates themselves suffered; enjoyed their own self-created ups and downs, and the Iowa Republican leaders largely stayed neutral in the race.

Grassley, himself, did not endorse in the race and expects to stay out of it until the party picks a nominee.