But the more explosive charges from outside groups against Mr. Obama have often drawn closer scrutiny this year for their volume and the cultural and racial sensitivities they tend to touch, and, occasionally, seek to exploit.  In Mr. Obama’s case, the messages have frequently sought to paint him as foreign, like the chain e-mail messages sent for months to Jewish areas of Florida, suburban Philadelphia and other swing states that portray Mr. Obama as Muslim (he is Christian). This week, a hate group calling itself the League of American Patriots distributed fliers to as many as 50 homes in Roxbury, a mostly white town in northern New Jersey, portraying Mr. Obama as Osama Bin Laden and including language that was derisive of black people.  The Southern Poverty Law Center, which tracks extremist groups, said the fliers, initially reported by The Star-Ledger in Newark, were the first overtly racist printed tracts of their kind this election season.  The advertisements running here against Mr. Obama come from a group called Freedom’s Defense Fund, a political action committee based in Washington that was formed four years ago and raises money from conservatives around the country. The advertisements have stood out because of the group’s connections — including to its paid consultant, Jerome S. Corsi, the author of the highly negative, largely discredited political biography of Mr. Obama, “Obama Nation” — and what local critics say are their racial overtones.  “That’s all they are — race oriented,” said Ed Bruley, the chairman of the Democratic Party of Macomb. “I think some people will be affected by it, others will see it for what it is.”  It is a view shared by Democratic leaders, including Gov. Jennifer Granholm, who, in a recent interview with MSNBC, said of the advertising campaign, “The fact that it is being run in a predominantly white suburb tells you that there is an explicit effort to try to divide people by race.”  Todd Zirkle, the executive director of Freedom’s Defense Fund, said race had “zero” to do with the spots. “That’s the standard retort when you want to say ‘Don’t listen to these people,’ ” Mr. Zirkle said.  He said the group’s intention was to show Mr. Obama’s affiliations — although Mr. Obama and Mr. Kilpatrick were never known to be close.  He said coming spots would highlight Mr. Obama’s ties to two white men, the developer Antoin Rezko, a former financial backer of Mr. Obama’s who has been convicted of fraud, and to the Weather Underground founder William Ayers, with whom Mr. Obama worked on an education commission in Illinois and whose past Mr. Obama has repudiated.  Mr. Zirkle said a fifth spot would highlight Mr. Obama’s supposed support for the Kenyan prime minister, the opposition leader Raila Odinga. Mr. Zirkle did not share that script, but Mr. Corsi’s book asserts, without substantiation, that Mr. Obama has been a close supporter of the African leader. Mr. Obama remained neutral in the Kenyan elections.  Officials with Freedom’s Defense Fund, which gives Mr. Corsi’s book to its donors, said they paid Mr. Corsi only to help write fund-raising appeals. Federal returns show he was paid $15,000 as a fund-raising consultant. But the details of his book provide a thread that runs through several of the anti-Obama groups.  One of them is the National Campaign Fund, a group directed by Floyd Brown, who produced the Willie Horton attack ads against Gov. Michael S. Dukakis of Massachusetts in the 1988 race. An advertisement Mr. Brown hopes to run against Mr. Obama this fall — and now on his group’s Web site — cites Mr. Corsi’s book in trying to paint Mr. Obama as a Muslim.  Mr. Brown said in an interview that he had spoken with Mr. Corsi, whom he said he has known “for years,” but Mr. Corsi is not listed as a formal consultant. Federal filings show that Mr. Brown’s group has spent more than $60,000 for a direct mail campaign, the content of which he would not share.  Disputed claims that Mr. Corsi has made about Mr. Obama’s abortion stance have dovetailed with those of a group that recently ran a commercial in Dayton, Ohio, accusing Mr. Obama of supporting “infanticide” (he does not).  The group, the Black Republican PAC, has several connections to the Freedom Defense Fund. They share the same treasurer, Scott B. MacKenzie, who had also worked on Ronald Reagan’s presidential campaigns in 1980 and 1984, as well as those of Jack Kemp and Patrick J. Buchanan. Mr. MacKenzie’s office is located in the direct mail firm working with both groups, BMW Direct, whose chief operating officer, Michael Centanni, is also the chairman of the defense fund.  Mr. Centanni said he has no connection to Mr. McCain’s campaign. He said Freedom’s Defense Fund, with relatively scant resources to spread nationally, decided it could have the most impact by focusing its presidential efforts here for tens of thousands.  “We feel Obama can’t win the presidency without Michigan and he can’t win Michigan without Macomb,” he said. “We’re relatively small, but we’re trying to be effective and relevant.”  Bill Burton, a spokesman for Mr. Obama, said, “Considering that these ads have only run on television a couple of times, this group is getting a wealth of attention it would otherwise never get just by this article appearing in The New York Times.”  Macomb is where the Democratic pollster Stan Greenberg helped define the term “Reagan Democrat” in the mid-1980s, conducting a series of polls to conclude that white, unionized workers came to believe Democrats had abandoned them for, in part, the poor and African-Americans.  Mr. Greenberg returned this year with his Democratic advocacy group, Democracy Corps, to find that racial attitudes among white workers had grown less hostile, though concerns had not disappeared.  Union officials have worked to dispel those concerns. Waiting in a car outside a Dollar Store here, a retired auto worker named Angie Christel, 78, who is white, said the union had dismissed for her the notion that Mr. Obama was Muslim. “I thought he was Muslim until I got the letter in the mail,” Ms. Christel said, “and he was raised by all white people.”  A version of this article appears in print on September 24, 2008, on Page A1 of the New York edition with the headline: PINPOINT ATTACKS FOCUS ON OBAMA. Order Reprints| Today's Paper|Subscribe
A series of ads in Michigan highlights this year’s roughest political attacks: narrowly aimed shots from small groups.