Arthur Levitt, former head of the SEC, tried but failed to prevent accounting firms from being accountants and consultants for a single firm. That might (stress might) have made a difference with Enron. In any case, after Enron, it now looks like a pretty good idea.
In The Hill, Alexander Bolton nicely untangles the web of money contributions and Washington hardball that led thirteen Senators to bully Levitt into backing off.
Most even threatened to cut his funding if he didn’t relent.