Four years ago, as Mayor Adrian M. Fenty faced an increasingly disaffected electorate, a trio of D.C. Council members began positioning themselves for greater power.

One would ride Fenty’s troubles to become the city’s next mayor. Another would rise to capture the council chairmanship. A third would assume more influence over the District’s economic development projects with an eye on citywide office himself.

Vincent C. Gray, Kwame R. Brown and Harry Thomas Jr. were viewed by their supporters as homegrown heirs to the best parts of former mayor Marion Barry’s legacy. They were African American Democrats who understood the city’s complex racial history and hoped to shape its future. They would redeem a generation of black political leadership tainted by Barry’s personal foibles and fiscal mismanagement.

Instead, the men have plunged the District into a new round of crisis, triggering reminders of the worst aspects of the Barry era and fears that the city’s political culture is regressing.

Last week, Brown resigned the council chairmanship before admitting to bank fraud and a campaign-finance violation. Thomas relinquished his council seat in January and is on his way to jail for embezzling $353,500 in taxpayer funds intended for children’s programs.

Federal investigators have secured guilty pleas from two campaign aides to Gray on felony charges that include making illegal campaign contributions and destroying records. The probe is ongoing; the mayor, who ran for office with the slogan “Character, Integrity, Leadership,” has denied wrongdoing.

“Politicians will say there’s a culture of corruption, and often people say it’s rhetoric,” said Bryan Weaver, a Democratic activist who has campaigned for the council. “But when it comes to D.C., there’s a culture of corruption that really exists. What gets passed off as politics as usual are huge ethical lapses.”

Yet for all the familiar talk of malfeasance engulfing the D.C. government, Washington — with its cash-rich treasury and booming downtown — is far different from when Barry presided.

The city is wealthier and no longer majority black, and its relationship to its political leadership is more remote. Under Barry, whose rise from modest Mississippi roots to the mayoralty crystallized the aspirations of African Americans, black professionals obtained city jobs and contracts that had long been the domain of whites. Legions of black youngsters got work through Barry’s summer employment program, winning him the loyalty of a generation of District natives. White Democrats embraced Barry as well, at least in the early years of his mayoralty, when they viewed him as a symbol of racial progress.

“People were personally invested in his administration, and there was a lot of pride around it,” said William P. Lightfoot, a former at-large D.C. Council member. Now, with the waves of affluent newcomers who have moved to the District, many of them disengaged from local politics, “many people in this town do not rely on the government,” he said. “Their personal daily lives are not affected.”

Race remains a strong undercurrent to the rhythms of the city, but home rule and black empowerment are no longer novelties.

“We are not vested emotionally with the idea that these are our black politicians,” Lightfoot said. The scandals, he said, “aren’t viewed as racial failure. It’s a failure of individuals.”

The current spate of investigations is distinct from those that defined the District during the 1980s and early 1990s. Fourteen officials in Barry’s administration were convicted or pleaded guilty to crimes stemming from their official duties.

Yet what caught the world’s attention was the FBI surveillance tape capturing Barry smoking crack at a downtown hotel, a crime for which he was convicted of a single misdemeanor drug-possession charge. A federally imposed control board took over the District’s finances during his fourth term, but no elected official was convicted of a felony.

The current investigations concern a “breach of public trust,” said Anita Bonds, an aide to Barry during his mayoralty who chairs the D.C. Democratic Party. Barry’s troubles, she said, centered on personal weakness.

Now, she said, “We’re disappointed, and we’re disappointed in a different way.

“People thought they had made the best choices, and people were pleased with those choices,” Bonds added. “Whenever things don’t work out the way you envisioned it, you can second-guess yourself.”

Barry, in a telephone interview, said: “The people in this city know of all the outstanding concrete things I’ve done in my 16 years as mayor, in my years on the city council — people can touch and feel a lot of things, so I don’t have to defend my excellent record. The people already spoke. They elected me four times, and they’re not dumb people.”

Myriad locales have long traditions of corruption, whether it’s Illinois, where the past two governors have gone to prison, or Rhode Island, where the mayor of its largest city served a four-year sentence for racketeering, or Prince George’s County, where former county executive Jack B. Johnson received a federal prison term of more than seven years for taking bribes.

Jamie Raskin, an American University law professor and a longtime observer of the District government, said insular politics often breeds corruption. “Places where politics is a family business, public integrity always suffers,” he said, adding that “there’s a dimension of that in the District.”

Thomas and Brown come from families with deep political roots in the District. Thomas’s father, Harry Sr., served on the D.C. Council for 12 years. Brown’s father, Marshall, is a longtime political operative who advised Barry. Gray, meanwhile, was educated in the city’s public schools and at George Washington University; he went on to run the city’s Department of Human Services under Barry’s successor, Sharon Pratt.

In their campaigns, all three men touted themselves as “native Washingtonians.”

The mayor who followed Barry came from out of town. Anthony A. Williams, born in California, raised in Connecticut and brought to the District by a federal job, used his outsider status to win election and overhaul the government, raising hiring standards and improving services. As the economy soared in the early 2000s and construction cranes became ubiquitous atop the city’s skyline, the District underwent a renaissance.

Williams was succeeded by Fenty, who represented a new breed of homegrown leadership, climbing from neighborhood activism to elected office by focusing on the delivery of basic government services. He snubbed the icons and rejected the rituals associated with the District’s traditional political culture, alienating the parts of the city where Barry had been popular, neighborhoods that supported Gray, Brown and Thomas.

For all the change, however, spasms of public corruption persisted. In 2007, a tax-assessment manager was caught running a $48 million scam out of her office. Technology officials were implicated in a bribery and ghost-payrolling scheme. And the Fenty administration faced questions about construction contracts it doled out to the mayor’s fraternity brothers. In the past several years, federal and city investigators have questioned or probed spending by seven council members.

“What you have is serial criminality, bad judgment and stupidity,” said council member David A. Catania (I-At Large). “That is the trifecta that is undermining our government, and what’s sad is the instability of it all. These past few years, it’s one after another, and the collective gag reflexes of the population have been expired.”

The link between Barry and the current scandals, Catania said, is that the former mayor “established a precedent where senior officials would not be held accountable for their actions.”

“There’s a culture that the powerful don’t live by the same rules,” Catania said, “and that has come to haunt some of the members who are not Marion Barry.”

Asked about Catania’s remark, Barry said criminal wrongdoing in his administration was “isolated to a few people” and that he “has not engaged in or condoned any pattern of misconduct.”

In the cases of Thomas and Brown, political observers noted the distinctions in their transgressions. While Thomas took taxpayer funds intended for programs benefiting children, Brown lied about his income on loan documents and authorized illegal cash disbursements from his campaign fund.

“Kwame got caught up with keeping up with the Joneses,” said Michael Fauntroy, a George Mason University professor and longtime D.C. resident. “He didn’t resign for something he did on the council. We need proportion and context in our politics. It’s far too easy for people to say it’s all the same. There’s a difference between stealing money for kids and filling out false mortgage documents.”

Although the felony charge had no direct bearing on Brown’s public duties, U.S. Attorney Ronald C. Machen Jr. on Friday said he had to demand his resignation as part of the plea deal. “This is a man who controls billions of dollars in the city budget,” Machen said. “How would you feel if we left him in office and an even greater fraud was perpetrated on the public?”

The downfall of Thomas and Brown might represent the chance for generational change in D.C. politics. Barry, 76 and beginning his third council term, is approaching the end of his political career.

But who will take their places?

Because of its non-state status, the District has been viewed as a political dead end. Even if a candidate makes it to the council, or the mayor’s office, the horizon after that does not include a governor’s job or a U.S. Senate seat.

As a result, party leaders have long struggled to draw talent.

“There’s no real bench,” Faunt­roy said. “There’s no place, other than the council, where one can cut their legislative teeth.”

Weaver, a community organizer and former Advisory Neighborhood Commission member in Adams Morgan, twice has lost races for the council. Persuading prospective voters to focus on issues such as ethics and misspending, he said, can be “absolutely frustrating.”

“People are transactional in their politics,” he said. “They’re willing to overlook the bigger stuff because the councilman was there. Marion doesn’t pay his taxes, but they say, ‘I got my first job from him.’ ”

The race to succeed Thomas in Ward 5 drew 11 candidates, out of which Kenyan R. McDuffie, a onetime postal worker who became a lawyer and served as an aide to Gray, emerged victorious.

His supporters, a multiracial coalition, tout him as an independent voice, reflective of a new generation of politicians in the District. He is a native Washingtonian.

His campaign slogan was “Restoring our Faith in Leadership.”