Read the full Iowa State University poll

The polls in Iowa change by the day.

On Sunday, the prestigious Iowa Poll of the Des Moines Register had Barack Obama leading Hillary Clinton 28 percent to 25 percent among likely Democratic caucus-goers, and Mike Huckabee ahead of Mitt Romney by 29 percent to 24 percent. Earlier today, the Pew Research Center weighed in with a poll on the Democratic side that had Clinton ahead of Obama by 31 percent to 26 percent with John Edwards third at 19 percent.

Now, a new Iowa State University survey puts Clinton on top with 30.8% of likely caucus attendees, followed by John Edwards at 24 percent and Obama at 20.2 percent. On the Republican side, Romney leads Huckabee 25.4 percent to 22.1 percent with Rudy Giuliani clocking in third at 15.8 percent.

Jim McCormick, the University’s political science chairman who directed the poll says: “Most of the top two candidates are still polling within the margin of error, which means there is no clear cut choice. The biggest explanation for that is the volatility that still exists among those people who are likely to caucus. We’re getting real differences from them, even when they’re polled just days apart. And this uncertainty indicates that they’re really not committed to these candidates yet.”