"Don't listen to them, don't listen to them," he said of the critics. "Don't let somebody tell you that you are not part of this process - because your future is at stake, and America's future is at stake."
Speaking at a concert hall packed with students at Grinnell College, he said students who attend school in the state have established residency by doing so and are able to take part in the caucuses. The Illinois senator is polling strongly among young people in Iowa and could have much to gain in the close presidential nomination race from coeds willing to cut short their holiday and take part in the caucus.
Democratic rivals are divided over whether Obama is playing by the spirit of the rules. Sens.and have criticized the effort, with Dodd saying, "That may be the way politics is played in Chicago, but not in Iowa." Clinton said she's encouraging people who live and pay taxes in Iowa to show up. But John Edwards said the rules are "fairly liberal" when it comes to out-of-state students caucusing.
Obama told the students in Grinnell that they have a historic opportunity to pick the next president because it could take as few as 150,000 people to determine the caucus winner. "In this election, the winner of the Iowa caucus has got a huge head start in terms of being the Democratic nominee," he said. "I don't think there should be any doubt that the Democratic nominee is going to win the presidency."
Obama also made a late evening appearance at the University of Iowa, where he told more than 2,000 students that "if you're going to be out of state, I want you to come back and caucus."