A majority of District residents say Mayor Vincent C. Gray should resign, according to a new Washington Post poll that reveals how deeply the continuing campaign corruption scandal has eroded the city’s support for its mayor.

Gray’s support is dwindling even among his political base, with 48 percent of African Americans saying he should resign. Among those who say they voted for him in 2010, nearly four in 10 think that he should step down.

Fifty-four percent overall say Gray should resign, while 37 percent say he should not and 9 percent have no opinion.

Gray has said the federal investigation into his campaign has not affected how his administration is running the District, but only three in 10 approve of the job he is doing as mayor. Forty-four percent say the city would be better off if he left office.

The mayor’s political supporters and other city leaders have rallied behind him, saying calls for his resignation are premature because he has not been accused of wrongdoing. But only 22 percent of residents surveyed say they view Gray as honest and trustworthy.

The public sentiment that Gray should resign crosses virtually all demographics in the city, according to the poll. Across categories of sex, ideology, party identification, income, age and geography, more say Gray should resign than not. African Americans and those 65 and older are closely divided on whether Gray should step down.

The numbers suggest that Gray cannot rely on a deep well of support from any particular group as he fends off questions about the investigation and his continued tenure as mayor. East of the Anacostia River, an area where 82 percent of voters preferred Gray in the 2010 Democratic primary, a plurality of residents now think he should step down, 48 percent to 43 percent.

So far, three campaign associates have pleaded guilty to felonies, including charges relating to secret payments to an opponent and a clandestine “shadow campaign” to get Gray elected.

Dorothy Kelly, 73, said Gray must resign because she thinks he had knowledge of the illegal activity in his campaign. “If you’re working around people, you know what’s going on. I think he knew what was going on and ignored it,” said Kelly, a retired secretary who lives in the Bellevue neighborhood of Ward 8.

The survey also shows a continuing drop in Gray’s popularity since The Post’s last D.C. poll. Only 33 percent of the city’s voters have a favorable opinion of Gray, down from 47 percent in May 2011 and a pre-election high of 60 percent.

The new data show Gray’s favorability has dropped most precipitously among women — particularly white women. Thirty-seven percent said in May 2011 that Gray was honest and trustworthy compared with 6 percent today. Among black women, his job approval has plummeted 18 points, to 32 percent, in the same period.

Opinion driven by evidence

Talk of Gray’s political fate accelerated last week after a public relations consultant with ties to the mayor, Jeanne Clarke Harris, admitted in federal court to helping to orchestrate a “shadow campaign.” The effort was funded by $653,800 from a prominent city contractor, she said.

Citing the details revealed in court last week — prosecutors said the shadow effort was coordinated with Gray’s official campaign — three D.C. Council members have called on him to resign.

Gray’s campaign had previously been rocked by allegations that it paid fellow mayoral candidate Sulaimon Brown to verbally attack incumbent Adrian M. Fenty. Prosecutors have not alleged that Gray participated in or had knowledge of either scheme.

Gray has not detailed his knowledge of the spending but has lamented the campaign scandals in general terms. “This is not the campaign that we intended to run,” he said July 11.

Louis Clark, 65, said his opinion that the mayor should resign is driven by evidence. “First of all, there’s more than the appearance of wrongdoing, in terms of campaign finance violations. These people were integral to the campaign itself,” said Clark, a lawyer who lives in Chevy Chase. “I don’t think it’s believable that he had no idea what was going on.”

Clark, who is white and voted for Gray, said that if the mayor didn’t know about the secret spending, “it raises doubts about his ability to run a campaign and subsequently the administration.”

Gray has called on residents to draw a distinction between his campaign and his administration. He pointed to his accomplishments, including a declining unemployment rate that at 9.1 percent is the lowest since April 2009. He attributed the rate partly to his “One City, One Hire” initiative, an ambitious effort to match 10,000 unemployed residents with private jobs.

But the poll, conducted Sunday to Tuesday via land-line and mobile phones, shows that the public gives little credit to the administration amid campaign scandals.

Only one in four respondents agree that Gray is running an ethical administration. Among those questioning the administration’s ethics are about half of those who said they voted for Gray in 2010.

In addition, more than six in 10 residents say Gray is doing a less-than-satisfactory job on his main policy priority — creating jobs for city residents — and over half say he is not doing well on improving schools or services.

Kelly said she had hoped Gray would counter his predecessors in getting more services to poor residents and those living east of the Anacostia River. But she said she still thinks that her community is not getting enough attention.

“When it’s time to vote . . . then they come around,” she said.

Wider problems seen

Meanwhile, there is a broad sense that the ethical questions and criminal investigations represent a challenge in city politics.

More than two-thirds of poll respondents say they have closely followed the recent scandals — including the federal pleas and resignations of D.C. Council Chairman Kwame R. Brown (D) and council member Harry Thomas Jr. (D-Ward 5). Among registered voters, three-quarters say they are watching very closely or somewhat closely.

About three in four say the scandals represent wider problems in city politics rather than isolated incidents. Forty-four percent say they think corruption in D.C. government is getting worse.

The poll of 1,002 D.C. adults has a margin of error of plus or minus four percentage points.

Those paying close attention are more likely to disapprove of Gray’s tenure, think that he should step down and consider corruption to be worsening or a sign of broader problems.

At the same time, there is little sense that District leaders are being unfairly targeted by federal authorities.

Only 8 percent of poll respondents say they felt the investigations into Gray, Thomas and Brown have been unfair. Six percent cite race — all three politicians are black — as having something to do with the probes. Among black residents polled, 13 percent say the politicians were being unfairly targeted, with 9 percent citing race as a factor.

Morris Gordon, 33, a black resident who supported Gray in 2010, said he thinks the probes have been fair but “as of yet” he does not think Gray should resign. “That’s beyond us,” he said, referring to the public. “It’s up to the U.S. attorney’s office.”

Gordon, who lives in Northeast and works in construction management, said he needs definitive evidence of wrongdoing by the mayor. “It needs to be a blatant display of corruption through a legal means,” he said. “It can’t be mere speculation.”

There is evidence of a continuing divide between opinions on the District’s progress and opinions on its political leadership.

Compared with May 2011, more residents think the city is on the wrong track — 45 percent vs. 36 percent of those polled 14 months ago. Those figures are comparable to summer 2006, when the city was rocked by a crime wave and concerns over public education and affordable housing were widespread. But they are nowhere near the depths plumbed in the early to mid-1990s, when 70 percent or more thought the city was on the wrong track.

Gray’s current approval ratings — at 29 percent, a near-record low for a D.C. mayor — are significantly lower than Marion Barry’s 50 percent approval in May 1996. Then, 36 percent of residents said Barry should step down as mayor.

At the time, Barry set off rumors about his physical and emotional health when he unexpectedly announced that he would take a two-week retreat to reflect and rejuvenate.

The beginning of his fourth term in office had been filled with setbacks, from his battle with prostate cancer to the congressional decision to establish a financial control board.

Despite that, 25 percent of residents said then the city would be worse off without Barry. Today, only 5 percent say the city would be worse off without Gray.

Jon Cohen and Scott Clement contributed to this report.