In 1978, the FBI performed an undercover sting operation that resulted in the conviction of six US congressmen and one senator for accepting bribes. From what I've read, it seems like it was driven by the FBI itself - they created a fictitious company, attempted to get various legislators and businessmen to accept bribes from them, and then prosecuted the ones who took the bribes.
Why is that not considered entrapment? It certainly was a close thing, given in Kelly for example the district court originally found it entrapment before being overruled on appeal. I've read a few articles, such as this one, that summarized the arguments to some extent, mostly mentioning the ruling and the Brandeis dissent in Casey v. United States, but it seems difficult to understand the exact line here.
Also, would this be considered entrapment today? Is the standard different?