By JEFF ZELENY


WILLIAMSBURG, Iowa-Pauline McAreavy voted for President Obama. From the moment she first saw him two years ago, she was smitten by his speeches and sold on his promise of change. She switched parties to support him in the Iowa caucuses, donated money and opened her home to a pair of young campaign workers.

But by the time she received a fundraising letter last month from the Democratic National Committee, a sense of disappointment had set in. She returned the solicitation with a handwritten note, saying, “Until I see some progress and he lives up to his promises in Iowa, we will not give one penny.”

“I’m afraid I wasn’t realistic,” Ms. McAreavy, 76, a retired school nurse, said on a recent morning at her home here in east-central Iowa.

“I really thought there would be immediate change,” she said. “Sometimes the Republicans are just as bad as Democrats. But it’s politics as usual, and that’s what I voted against.”

One year after winning the election, Mr. Obama has seen his pledge to transcend partisanship in Washington give way to the hardened realities of office. A campaign for the history books, filled with a sky-high sense of possibility for Mr. Obama not just among legions of loyal Democrats but also among converts from outside the party, has descended to an unfamiliar plateau for a president whose political rise was as rapid as it was charmed.

Interviews with voters across Iowa offer a window into how the president’s standing has leveled off, especially among the independents and Republicans who contributed not just to his margin of victory in the caucuses here but also to the optimism among his supporters that his election would be a break from standardissue politics.

In Iowa, Ms. McAreavy fears that the president’s health care plan will shortchange her Medicare benefits and mean infrequent mammogram examinations. She worries that his decision on Afghanistan will mean that her son, a member of the Iowa National Guard, will return to the battlefield. And she believes that too many of Mr. Obama’s actions are rooted in Democratic politics.

“All my Republican friends-and independents-are sitting back saying, ‘Oh, what did we do?’ ” Ms. McAreavy said. “I’m not to that point yet, but a lot of people are.”

Mr. Obama still has generally strong approval ratings and the opportunities that come with a Democratic majority in Congress. Public opinion about him remains in flux, particularly as he heads into the endgame of a push to overhaul the health insurance system and nears a decision about whether to expand the war in Afghanistan.

But an erosion of support from independents and disapproval from Republicans suggests that the coalition Mr. Obama built to win the White House is frayed.

In few places did people get a longer and closer look at Mr. Obama than in Iowa, a swing state home to deep strains of both conservatism and liberalism. Mr. Obama was a constant presence here during the formative months of his candidacy.

As Mr. Obama approaches the anniversary of his election, the sense of possibility and the dash of romance that moved many voters are no longer apparent. The challenges of governing have eaten away at the optimism. The pace of government intervention has also jarred many voters.

The Iowa Poll, published in September by The Des Moines Register, showed that Mr. Obama’s approval rating had fallen to 53 percent, from 64 percent in April. In interviews , the economy emerged as one of the most worrisome undercurrents.

“I’m scared,” said Chris Bollhoefer, 49, who lost his job two years ago at Maytag in Newton. “The competition right now, with all the people who have lost jobs that are highly qualified, really puts you up against the wall trying to compete.”

Mr. Bollhoefer said he approved of the job Mr. Obama was doing. “It’s inspirational to me that he’s trying to do something different,” he said.

Even with the complaints, many Democrats said the president had single-handedly improved the United States’ image in the world. They said he had already accomplished a great deal, considering the raft of crises that greeted him .

Candi Schmieder, 40, said she trusted the president. The election in Iowa County, where she lives, ended in a tie in November. Mr. Obama won by 14 votes after absentee ballots were tabulated. If a re-election were held today, she said, she feared that the outcome might be different.

Ms. Schmieder, who had never been involved in politics but said she had been drawn to Mr. Obama by his books, said: “Given all the situations that he’s dealing with-the economy and the war-I think it’s going to take some work.”



‘‘I think it’s going to take some work.’’

CANDI SCHMIEDER
A 40-year-old resident of Marengo, Iowa, who says she still trusts the president. / PHOTOGRAPHS BY SALLY RYAN FOR THE NEW YORK TIMES



‘‘I really thought there would be immediate change.’’

PAULINE McAREAVY
A retired school nurse, 76, who switched parties to vote for Obama