Rule-Based Regulation vs. Principle-Based

The Financial Page column in New Yorker magazine has a thought-provoking discussion about rule-based regulation vs. principle-based financial institution regulation that has some relevance to federal ethics regulation philosophies.

Here's an excerpt:

As the press has noted, the plan would consolidate our myriad and overlapping regulators into fewer, bigger ones. But the most interesting thing about it is something subtler: a push to move from our current system of regulation—often known as “rules-based”—toward a “principles-based” approach. In a rules-based system, lawmakers and regulators try to prescribe in great detail exactly what companies must and must not do to meet their obligations to shareholders and clients. In principles-based systems, which are more common in the U.K. and elsewhere in Europe, regulators worry less about dotted “i”s and crossed “t”s, and instead evaluate companies’ behavior according to broad principles; the U.K.’s Financial Services Authority has eleven such principles, which are often deliberately vague (“A firm must observe proper standards of market conduct”). This approach gives companies more leeway in dealing with investors and customers—not every company needs to follow the same rules on, say, financial reporting—but it also gives regulators more leeway in judging whether a company is really acting in the best interests of shareholders and consumers.

Which ethics areas are best suited to principles-based approaches and which require rules-based approaches?