Experts say the majority of campaign finance law violations are clerical errors or missed deadlines, and are rectified by the parties involved. Many result in civil penalties — President Barack Obama’s 2008 campaign paid a $375,000 penalty to the F.E.C., largely for failing to notify regulators of contributions totaling $1,000 or more within 48 hours of receiving them.
But other cases are more extraordinary, like the vast fund-raising operation that enabled the Watergate break-in.
In fact, quite a few recent high-profile political scandals have had a campaign finance twist. Let’s take a look.
A report by a special counsel to a state legislative committee had said that Mr. Bentley encouraged “an atmosphere of intimidation” around his staff to keep them from speaking of his relationship with Ms. Mason, and that he had directed state employees to cover up the relationship. (Mr. Bentley had denied a physical relationship with Ms. Mason long before he resigned, despite recordings that suggested physical intimacy.)
Central to Mr. Bentley’s resignation was a guilty plea to two misdemeanor charges: failing to file a major contribution report and knowingly converting campaign contributions to personal use.
The report describes how Mr. Bentley tried to use a member of his security detail to break up with Ms. Mason on his behalf, and how Mr. Bentley demanded that she be allowed to travel in official vehicles after she left the state’s payroll.
Before the plea deal, the Alabama Ethics Commission had said it had probable cause to find that Mr. Bentley had committed felonies before he resigned, and had referred its findings to prosecutors.
The presidential candidate’s affair and child
An illicit affair, a pregnancy and a scheme to hide them during the 2008 presidential race.
That would become the focus of a trial in 2012 over whether John Edwards, a former Democratic presidential candidate, vice-presidential nominee and senator, broke campaign finance laws as part of the cover-up. A two-year investigation led to his indictment by a federal grand jury in 2011.
Mr. Edwards began the affair with a campaign videographer, Rielle Hunter, in 2006; she became pregnant the next year. Prosecutors said Mr. Edwards had used about $1 million to hide Ms. Hunter from his wife, Elizabeth Edwards, and the public. They also said he initially had an aide claim paternity of the child, who was born in 2008. Mr. Edwards admitted the child was his in 2010.
Mrs. Edwards died that December after battling cancer. One of her closest friends testified about the emotional turmoil Mrs. Edwards went through to believe that her husband had not conceived a child with Ms. Hunter.
A jury could not reach a verdict on five charges of campaign finance fraud and conspiracy, and found Mr. Edwards not guilty on one other charge. Federal prosecutors later said they would not retry him.
The stays by donors in the White House’s Lincoln Bedroom
The Democratic Party’s fund-raising tactics during the 1996 presidential campaign, including overnight stays for top donors in the White House’s Lincoln Bedroom, became the subject of much controversy.
It would emerge that President Bill Clinton had personally approved a plan, years earlier, to reward Democratic donors and fund-raisers with meals, golf outings and jogs with him, as well as stays in the Lincoln Bedroom to “energize” them for his re-election campaign. Critics referred to the selling of the Lincoln Bedroom.
After Mr. Clinton’s re-election, the administration released a list of 938 guests who stayed in the Lincoln Bedroom and other rooms, including some who did not donate.
Mr. Clinton largely defended the visits, saying that the guests had stayed as friends, not as contributors.
The scandal was soon overshadowed by revelations of Mr. Clinton’s affair with a White House intern, Monica Lewinsky.
The vice president’s visit to a Buddhist temple
Another scandal tied to that campaign would follow Vice President Al Gore for years.
In 2000, a longtime fund-raiser for Mr. Gore was convicted of five felony counts for helping arrange illegal donations to the Democratic Party and its candidates in 1996. About $55,000 of that was in connection with a visit by Mr. Gore to a Buddhist temple in the Los Angeles area during the campaign.
Prosecutors said that the fund-raiser, Maria Hsia, arranged for nuns and monks to write checks to make it seem that they were the donors to the Democratic National Committee. But they were actually reimbursed by the temple, a religious, tax-exempt institution barred from making political contributions.
Mr. Gore’s credibility regarding what he knew came under scrutiny.
The scandal resurfaced during his failed 2000 presidential run. “Who’s he going to be today?” one television ad asked. “The Al Gore who raises campaign money at a Buddhist temple? Or the one who promises campaign finance reform?”
Alain Delaquérière contributed research.
Follow Mihir Zaveri on Twitter: @MihirZaveri.