WASHINGTON — Confronting his Republican opponents, President Barack Obama told Iowa Democrats on Tuesday that the stakes of the 2012 election are much higher than when the state launched his presidential bid four years ago.
‘‘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 to fully take root,’’ Obama said in a teleconference with Democrats attending precinct caucuses. ‘‘And that’s why this time out is going to be, in some ways, more important than the first time out.’’
Obama outlined his progress during the first term, telling activists in the live video link that because of their support, the Iraq war ended, a major health care overhaul bill was signed into law and the military’s ‘‘don’t ask, don’t tell’’ policy on gays was no longer in use.
‘‘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,’’ Obama said. ‘‘But we’ve been making steady progress as long as we can sustain it.’’
Obama wasted little time getting back in front of voters following a Hawaiian vacation spent largely out of the spotlight. On Wednesday, Obama will travel to Cleveland for an event focused on the economy.
Obama was seeking to rebut months of withering criticism from Republicans as GOP voters in Iowa took their first step in choosing a challenger among a field that included Mitt Romney, Rick Santorum, Ron Paul and others. Republicans have assailed Obama’s economic record, pointing to high unemployment rates, while tagging him as a president who has failed to live up to lofty expectations.
‘‘Three years later, the president’s promises of hope and change have been replaced with a record of failed leadership and policies that have made the economy worse,’’ Republican National Committee spokeswoman Kirsten Kukowski said.
Iowa looks to be among about a dozen states that could shift either way in the 2012 campaign, with Republicans pointing to voter registration gains as a positive sign heading into the fall. Iowa has switched its support in each of the past three elections, supporting Obama in 2008, Republican President George W. Bush in 2004 and Democrat Al Gore in 2000.
Trying to build on his 2008 win there, Obama’s campaign has opened eight offices in the state and had held more than 1,200 training sessions, phone banks and other events and made more than 350,000 phone calls to supporters since April.
The president’s re-election campaign emailed supporters a video of Obama’s Iowa victory speech in January 2008, arguing he has kept the promises he made that night: making health care more affordable, cutting taxes for the middle class, ending the war in Iraq and reducing the nation’s dependence on foreign oil.
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. There’s just isn’t anybody exciting their base, and if they can’t get excited, I just can’t believe they have a chance whatsoever,’’ said Danny Waterman, 65, a retired police officer who supported Obama four years ago.
Scott Rieker, a 35-year-old elementary school teacher, said he hasn’t agreed with everything Obama has done since winning the White House but many party loyalists are approaching the upcoming campaign with a greater sense of reality.
‘‘I’m not going to vote for anyone else, and I will make calls and knock on doors,’’ Rieker said. ‘‘But ... it’s more grounded in reality now. We thought that the world would magically change in four years, I think, when we were working last time.’’
Rieker and others listened as Obama sat in a chair with a flag behind him in a call monitored by Mitch Stewart, the Obama campaign’s battleground states director.
Skipping a fiery speech, Obama gave caucus-goers in Iowa an understated recitation of accomplishments and challenges. The address was marred by audio difficulties when the president sought to hear questions from two members of the audience.
Obama told party activists that he was ‘‘actually more optimistic now than I was when I first ran, because we’ve already seen change take place.’’ He said a key part of the 2012 campaign would be ‘‘reminding the American people of how far we’ve traveled and the concrete effects that some of our work has had.’’
Turning nostalgic at one point, Obama recalled the pivotal role that voters in Iowa played in his first campaign, when he shook up the Democratic political establishment by defeating Hillary Rodham Clinton in the caucuses.
‘‘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,’’ he said. ‘‘You guys inspire me every single day.’’
Meredith reported from Des Moines, Iowa. Associated Press writers Julie Pace and Jim Kuhnhenn contributed to this report.