"Because of you, because of all the memories I have of being in your living rooms, meeting you in a diner or seeing you over in a campaign office, I have never lost that same source of inspiration that drove me to embark on this journey in the first place," Obama told Democrats attending precinct caucuses.
Obama outlined his progress during the first term and asked party activists for their help as Republicans made their first step toward choosing a challenger among a field that included Mitt Romney, Rick Santorum, Ron Paul, and others. Beyond its early-voting status, Iowa is expected to be hotly contested in the fall election.
"We're battling millions of dollars of negative advertising and lobbyists and special interests who don't want to see the change that you worked so hard for to fully take root," Obama said. "And that's why this time out is going to be, in some ways, more important than the first time out."
"The problems that we've been dealing with over the last three years, they didn't happen overnight and we're not going to fix them overnight," he said. "We've been making steady progress."
Obama wasted little time getting back in front of voters after a Hawaiian vacation spent largely out of the spotlight. On Wednesday, he will travel to Cleveland for an event focused on the economy.
The president used the video teleconference to talk directly with voters, an approach that encountered some audio problems during the short speech and question-and-answer session. He was seeking to counter months of pounding by Republicans in Iowa and by the Republican National Committee, which has assailed Obama's economic record and tagged him as a president who has failed to live up to lofty expectations.
Iowa looks to be among about a dozen states that could shift either way in the 2012 campaign. Iowa has switched its support in each of the last three elections, supporting Obama in 2008, Republican President George W. Bush in 2004, and Democrat Al Gore in 2000.
In Des Moines, roughly 200 people gathered at a caucus site at Lincoln High School, making small talk and waiting for Obama to speak as a girls' basketball game was played in an adjoining gym. Several party loyalists said they thought Obama could reignite the loyal support he generated in 2008.
"No Republican candidate is exciting their base," said Danny Waterman, 65, a retired police officer who supported Obama four years ago.