Nearly two years ago, the political world could only marvel at the breadth of voter support for Barack Obama.

The new president had won over voters once thought to have abandoned his party for good. He’d found new reservoirs of support among groups many thought were tapped out.

He energized a coalition — made up of blacks, women, Latinos, young voters and large numbers of suburbanites — that some believed would keep Democrats in power for years to come.

A scant 20 months later, the Obama coalition is frayed and frazzled.

A majority of those who voted for Obama still approve of the job he is doing. But that number is eroding.

Surprisingly, support for the president among Latinos, young people and women has dropped as much as it has among groups that were considered less likely to stick with the president, such as white males, according to an analysis by the Pew Research Center for the People & the Press.

Support among suburbanites has dropped dramatically too, surveys show, while African American voters remain Obama’s most loyal constituency and his fiercest defenders.

The trend is familiar to political scientists. A plunge in approval is common after a president enjoys an early honeymoon period. The disapproval of voters from all walks of life and from across the country might be attributed to a sour economy, a sort of national queasiness.

“What we’re seeing is a general frustration with the inability of the government to fix the problems more quickly,” said Scott Keeter, director of survey research at the Pew Research Center. “This is expressed in anti-incumbent sentiment and negative opinions of the president. This also suggests that improvement in national conditions might be accompanied by an uptick in support for Obama.”

For that reason, approval ratings at this point in a presidency are a poor indicator of a president’s chances at reelection.

But dozens of interviews with Obama voters across five swing areas show that the warning signals are blinking for the president’s party.

Obama voters evince little interest in the midterm election. When they express goodwill toward the president, it rarely extends to his allies in Congress. Many do not consider themselves Democrats.

Pew’s survey experts routinely ask respondents to characterize the president in a single word. In their most recent poll, conducted this summer, more respondents than ever answered with the word “disappointing.”

Some who threw their lot in with Obama expressed a sense of being let down by the man who promised change and pledged to transform the country. Some attributed that to their own lofty expectations and, perhaps, their naivete. Others pointed to what they saw as his lack of focus on the still-faltering economy.

And some suggested they were simply hoodwinked by a smooth-talking politician.

“What I’ve come to the realization is that the president was an absolutely fantastic campaigner. He was a perfect preacher-slash-minister-slash-professor,” said Peter Gallo, a concert promoter in Raleigh, N.C. “He doesn’t have the skill to legislate, to build coalitions. He does not have the skill to bring people in and say, ‘Come on and let’s get this done.’”

Gallo’s words — in various ways — were echoed in Fairfax County, Va., outside Washington; in northern Nevada; in greater Philadelphia; in the suburbs of Ohio; and in a college town in southern Virginia.

All are regions crucial to Democrats. The president will need these voters in two years. His party needs them now.

The fast-growing Raleigh-Durham area was dominated by Obama in 2008. He took up to 70% of the vote in some counties — and helped turn North Carolina blue for the first time since 1976. Now, polls show that Obama’s healthcare plan is unpopular and that North Carolina voters are favoring Republicans in state legislative races.

About 2,500 miles away in Reno, Douglas Damon was drawn to Obama, in part, because he saw the candidate as a bridge builder.

“I believe in inclusivity. I believe America is a melting pot. I believed he really represented an opportunity to bring people together,” Damon, 64, said from the offices of his beverage manufacturing company in Sparks, Nev.

But Damon is disappointed that Obama hasn’t tried harder to work with Republicans. “His leadership skills have been lacking, in my mind,” he said. “He seems to dismiss opinions that differ with his vision totally.”

Nevada is the setting for a high-stakes fight between Senate Majority Leader Harry Reid and GOP challenger Sharron Angle. Damon is undecided in that race, and unapologetically calls himself a RINO — Republican in name only. “I’m totally disgusted with both parties right now,” he says.

But many who backed Obama refuse to assign him all of the blame for a struggling economy.

“He inherited substantial problems,” said Thomas Kovach, 46, a lawyer who lives in suburban Cleveland. “And no one should have thought those would disappear overnight.”

But in a portent of what could happen this fall, Kovach, an independent, said he may vote for Ohio GOP Senate nominee Rob Portman. “It really comes down to the individual,” Kovach said.

Obama’s pollster, Joel Benenson, argues that swing voters such as Kovach — not the more traditional Democratic constituencies — are the ones most likely to desert the president.

“Swing voters are acting like swing voters,” he said. “They swing. They remain very much in play. That’s where the decline has been. It’s not the core coalition.”

But while pollsters may disagree on the numbers, it’s clear some members of that core coalition are straying.

“The candidate and his campaign wooed young voters like me with the notion of change and that business as usual would no longer be the status quo,” said Jeremy Wintroub, 32, a television producer from Elkins Grove, Pa.

“We were told the influence of lobbies would be blunted; it has not been. We were told that Obama would find a way to work in a bipartisan fashion. His opposition has been totally unwilling to work with him. We were told he would go line by line through the budget and get rid of wasteful spending; instead he appoints a deficit commission made up of fiscal hawks who tell us the sky is falling.”

Obama captured the 18-to-29 vote in 2008, suggesting that Democrats had seized the imagination of so-called millennials. But economic hard times have unsettled that calculation, and many of 2008’s campus activists have had trouble finding jobs after graduation.

“There’s a pessimism,” said Courtney Jones, 21, from Virginia Beach, Va. “But you can’t go back to blaming Obama. You have to give him a chance.”

If there is a theme among Obama’s most steadfast supporters, it’s that more patience is required. Nowhere is that expressed more fiercely than in the nation’s urban black neighborhoods, even though they are among the hardest-hit by the recession.

One recent Saturday morning, Leona Leonard sat at a folding table in southwest Philadelphia, selling remnants from a recently closed jewelry store at a neighborhood festival. She recalled how it felt to watch an African American sworn in as president.

“I’m lucky to have lived to see it,” she said, lifting a hand to her heart.

The 52-year-old mother of six says Obama has not let her down. She supported the passage of the healthcare bill. The joblessness in her city is nearly 12%, but she doesn’t blame him for the country’s economic woes.

“I know he can’t turn this world around in a day,” she said. “I wish he’d stand up and tell everybody against him to be quiet. He needs to demand respect.”

A whopping 95% of black voters cast their ballots for the president in 2008. Their support has held more strongly than any other demographic group.

Obama in 2008 also did exceptionally well among the nation’s Latinos, although his support there is showing more wear and tear.

Sylvia Rojas, a 35-year-old nurse in Clifton, Va., says Obama lost her with healthcare.

As part of the medical profession, she has heard more than most about the bill and its likely effects, she said. She worries it will have unintended consequences — more paperwork, higher costs, more pressure on an already stressed healthcare system.

“I know he wants what’s best for this country, but from what I see happening, that wasn’t it,” Rojas said. “I am not really proud of my vote.”

Obama won 67% of Latino voters, compared with Democrat John F. Kerry’s 53% in 2004. The additional support meant a difference of thousands of Democratic votes in places like Nevada and Colorado, where the Latino community is long established, and in pockets of suburban Virginia where immigrants were drawn by economic growth and a lower cost of living.

But those areas, like much of the nation, are in worse shape now than even two years ago.

“There’s not enough industry here,” said Daniel Peters, a 37-year-old business consultant from Alexandria, Va. “The cost of living has risen and jobs have gone and people keep losing their homes left and right.”

But Peters, an Obama voter, says he doesn’t blame the president. “He’s not going to do it solo. He can only do so many things. Congress needs to help,” he said.

Peters added that he hadn’t yet tuned into congressional elections. He’s uncertain whether he’ll vote.

This is the attitude Democratic organizers are working against.

Latinos, blacks, young voters and women are less likely to take part in midterm elections than the broader electorate. Compared with presidential contests, midterm elections draw, on average, 26% fewer voters.

For unmarried women, Latinos and African Americans, the drop-off for midterms is more than one-third. And only about half as many young people turn out, according to data compiled by the polling firm Greenberg Quinlan Rosner.

Vijay Oberoi, 59, falls into the endangered-voter category. Two years ago, he knocked on doors for Obama in the neighborhoods around his rented home in Fairfax County, Va., in suburban Washington.

Oberoi, a father of two, has since lost his job as a sales associate at Circuit City. He remains unemployed, occasionally working as a courier to help pay bills. He recently told his son he could not afford to send him to college.

“I feel really embarrassed. I am his father and I was not able to help him,” he said.

Politics are now the furthest thing from the mind of the onetime Obama foot soldier. He doesn’t know whether he will vote in November. The president, he said, has let him down.

“How can I be happy? I am lower than the low,” he said. “He has to do something for people like me. And he hasn’t.”

joliphant@latimes.com

kathleen.hennessey@latimes.com