WASHINGTON — It was one of Capitol Hill’s most salacious scandals, featuring a senator’s affair with a campaign aide, an outraged husband, tens of thousands of dollars in hush money, illicit lobbying deals with Las Vegas power brokers and a dramatic intervention by a leading Christian ministry.

Now, three years after the fall of former Senator John E. Ensign of Nevada, thousands of pages of previously undisclosed documents reveal new details about the evidence the F.B.I. gathered against Mr. Ensign, who briefly flirted with running for president in 2012. The documents, which show that Mr. Ensign’s behavior was more brash than known at the time, also offer new specifics about the intense debate within the Justice Department over the decision to not prosecute Mr. Ensign, despite an aggressive F.B.I. investigation into the scandal.

The Justice Department recently turned over some 3,000 pages of internal documents from the case to a public watchdog group, Citizens for Responsibility and Ethics in Washington, known as CREW, after the organization sued under the Freedom of Information Act. The group provided the files to The New York Times, which in 2009 published an investigation of the Ensign case that prompted the F.B.I. inquiry.

Although the broad outlines of the case against Mr. Ensign have been made public, the documents disclose for the first time how much Mr. Ensign strong-armed political donors and business associates in 2008 to find lobbying work for Douglas Hampton, a top aide and close friend. Mr. Ensign was seeking the work in an attempt to placate Mr. Hampton because Mr. Ensign had an affair with Mr. Hampton’s wife, Cynthia Hampton, a campaign aide.