Barack Obama and Joann Larkins live less than a mile apart in Chicago's predominantly black South Side, but they inhabit very different worlds.
What connects her squalid flat and his colonnaded mansion is Antoin "Tony" Rezko, the former Obama donor and friend, who goes on trial for corruption next month - and was denounced as a "slum landlord" by Hillary Clinton in a dramatic and bitter exchange during last week's Democratic presidential debate.
Mr Obama’s past ties to the Syrian-born property developer, a well-known figure in Chicago politics for his financial largesse, have prompted new questions about the sound political judgement and clean ethics that he touts in his run for the White House.
The charges against Mr Rezko include one that he donated $10,000 (£5,050) to an unnamed political candidate from kickbacks allegedly taken from state contracts. The recipient is reported by Chicago media to have been an unknowing Mr Obama.
Separately, in 2005, Mr Obama, 46, struck a property deal with Mr Rezko's wife, Rita, despite the fact that her husband was already under criminal investigation. Mrs Rezko bought an empty plot next to the Obamas' $1.65 million home in the affluent enclave of Hyde Park, and later sold the Obamas some of the land so that they could enlarge their plot - a deal that the Illinois senator has since admitted was "bone-headed".
Mrs Larkins, 51, lives just seven city blocks away, in a district where posters advertise "dirt cheap properties" and "foreclosure advice". She moved there almost a decade ago, taking a subsidised apartment with her 20-year-old daughter and one-year-old grandson in a building that had fallen into neglect when run by Mr Rezko.
The family boiled water on the stove and draped plastic sheeting across the windows in an effort to keep warm during the city's bitter winters, as the heating was not working. Rubbish piled up uncollected and repeated requests for basic repairs were ignored.
"It was a terrible place to live: there were a lot of drug dealers and people fighting and getting shot," Mrs Larkins, a widow who receives invalidity benefit, told The Sunday Telegraph.
"The owners never took any interest in the place; they just wanted the rent money. We had to call the city just to get the garbage collected."
The 44-apartment complex was one of 30 low-income housing projects run by Mr Rezko and his partners with funds from the city during the 1990s. By early this decade, many were boarded up as bills and mortgage payments went unpaid, but Mr Rezko moved into the fast-food business, while tenants like the Larkins struggled with the legacy of his poor management.
Mr Rezko was also one of the first to spot the skills of Mr Obama, offering the then Harvard law graduate a job in 1991 and becoming an early financial supporter of the new state legislator, whose inner-city constituency included 11 of his housing projects.
Although Mr Obama makes much of his roots as a community activist in Chicago's poorest districts, he has said he had "no inkling" that there were problems with Mr Rezko's operations. But the signs should have been easy to spot, according to John Bartlett, of the Chicago-based Metropolitan Tenants' Association.
"The problems with Rezko were far from hidden. They were so bad that the city has had to take him to court. Anyone who wanted to look into Rezko's activities could have learned about them," he said.
Mr Obama has recently said that he "wasn't particularly knowledgeable" about Mr Rezko's activities. Asked if he should have investigated his donor's businesses, Bill Burton, Mr Obama's spokesman, said: "The senator has a long record of successfully fighting to reform ethics and diminish the role of money in politics." The reality of US politics is that even at state level, few politicians have the resources to check their donors' backgrounds thoroughly. But when candidates run for the nation's highest office, they find their finances trawled over by the media and their rivals' researchers.
Mr Obama has recently given to charity about $85,000 in donations from Mr Rezko and his associates, as he attempts to distance himself from his old friend and supporter. But the relationship will come under renewed scrutiny when Mr Rezko's trial starts on February 25.
There has been no suggestion of any wrongdoing in Mr Obama's ties to Mr Rezko. The senator has attempted to head off criticism by admitting that he failed to spot the "red flags" in pursuing a property deal that raised perceptions of possible impropriety at a time when other Illinois politicians were already turning their backs on Mr Rezko.
"The senator clearly showed a lack of judgment in continuing the relationship, although that does not necessarily mean a pattern of lack of judgment," said Cindi Canary, the director of the Illinois Campaign for Political Reform.
Jay Stewart, who runs the Better Government Association of Chicago, also expressed surprise at the property deal, saying: "Alarm bells should have been ringing. Everyone knew that Rezko was under investigation and Senator Obama should have expected this scrutiny. The mission is always to follow the money."
On the snowy streets of south Chicago last week, there was no escaping the evidence of the embarrassing connections: next to the Obamas' Secret Service-guarded home, a large "For Sale" sign now stands on the remaining plot of land owned by the cash-strapped Rezkos.
Rezko affair rattles skeletons in Clintons' closet
Just three days after Hillary Clinton taunted Barack Obama with taking money from Tony Rezko, the indicted businessman, a photograph of him standing between the former First Lady and her husband Bill appeared on the Drudge Report website.
Mrs Clinton insisted she had no memory of the encounter, which may have occurred when Mr Rezko attended a Democratic fund-raiser. But at a time when Mrs Clinton was trying to score points, it was a reminder that she and her husband have been dogged by financial questions for decades.
During the current campaign, Mrs Clinton has returned $850,000 (£429,000) in contributions linked to a convicted fraudster, Norman Hsu. Controversies during her husband's presidency included giving stays in the White House's "Lincoln bedroom" to donors, and a pardon for Marc Rich, a financier who fled abroad from fraud charges. His wife was a supporter.
The Clintons were hounded for years by a criminal investigation into their Whitewater land investment in Arkansas, although they were never charged. And the day after Mrs Clinton attacked Mr Obama's legal work on Rezko-related business, Mr Clinton was said to be preparing to sever ties with the investment firm of his friend Ron Burkle.
