In August 2007, three men who later became entangled in a Mississippi bribery scheme raised money for Sen. Joe Biden’s run for president.

A month later, two of the three were overheard in a phone call recorded by the FBI discussing federal legislation and a prospective meeting with Biden’s brother, Jim.

It’s unclear whether any meeting ever occurred or whether legislation was ever discussed, so the episode may mean little — except as an example of the potential political vulnerabilities that Barack Obama’s running mate brings to the Democratic ticket.

Longtime politicians always bring baggage to a campaign, and Biden is no exception.

Among the other grist he may provide for John McCain’s mill:

_The allegation of plagiarism that drove Biden from the 1988 presidential race.

_The history of Biden’s son, Hunter, as a Washington lobbyist. Since 2002, the firm Hunter Biden co-founded has represented a major constituent of Joe Biden’s, the University of Delaware, which has collected millions in federal funding.

_Donations to Biden’s campaigns totaling more than $200,000 in the past two decades from Delaware-based MBNA, the credit card company, and a similar amount from trial lawyers, including Richard “Dickie” Scruggs, one of the three men implicated in the Mississippi bribery scheme.

Since 1989, lawyers and law firms have contributed $6.5 million to Biden, according to the Center for Responsive Politics, a nonpartisan private group that tracks money in politics.

Among the problems the Obama-Biden campaign faces is some of Biden’s recent political rhetoric in which he tears down Obama. One Biden moment from the Democratic primaries that promises to be a Republican favorite: Biden’s comment a year ago that he didn’t think Obama was ready to be president.

Biden’s speaking style may resonate with many Americans, but his mouth has also gotten him trouble over the years.

He brilliantly and humorously skewered Rudy Giuliani, saying, “There’s only three things he mentions in a sentence: a noun and a verb and 9/11. I mean, there’s nothing else.”

But Biden spoke without thinking when he called Obama “clean” and said that customers cannot go into 7-Elevens unless they have a slight Indian accent.

In political campaigns, no black mark is too old to dredge up — again. Biden admitted back in 1987 that he had committed plagiarism while a freshman at Syracuse University law school and that he occasionally used other people’s words in his speeches without giving credit.

More recently, the Mississippi fundraiser and the FBI-taped phone call are the kind of information Obama’s opponents can make use of if they want to, despite the ambiguity of the circumstances.

Biden has returned at least $7,500 in campaign contributions from the three men and their families.

The overheard conversation between attorney Timothy Balducci and former Mississippi State Auditor Steve Patterson was recorded in September 2007 while the FBI was investigating a bribery scheme that toppled Scruggs, Mississippi’s most prominent lawyer.

Balducci tells Patterson at one point in the cryptic conversation that he was told “we really need to push on the Senate bill” and “get your man in line in the House if this comes out of the Senate,” according to the transcript.

On the tape, Balducci says he had spoken by phone to Jim Biden, Sen. Biden’s brother, “and we’re gonna meet the Bidens around noon,” according to the transcript.

Balducci said they would “meet with the black farmers at three.”

Around the time of the tape-recorded call, Biden and other lawmakers, including Obama, were pushing legislation to give thousands of black farmers a chance to seek compensation if they were denied loans or crop subsidies by the U.S. Department of Agriculture because of their race.

In December 2007, the Senate passed a farm bill that included language to help the farmers seek compensation if they missed out on an earlier settlement with the Agriculture Department in 1999.