The House and Senate are trying to boost approval ratings by passing a law banning insider trading by members of Congress — something that's already illegal.

After a recent book on insider trading by federal legislators was publicized by a "60 Minutes" television broadcast, members of Congress have been falling all over themselves trying to show that they don't do what the records clearly show they do — profit from their access to inside information.

Both the U.S. House and Senate are on the brink of passing the Stop Trading on Congressional Knowledge (STOCK) Act. But news reports describe the legislation as "mostly symbolic," ostensibly because what the bill purports to outlaw already is illegal.

Members of Congress are, of course, subject to the same insider trading laws that apply to regular citizens. But somehow not a one of them has been prosecuted for any of the myriad of questionable transactions outlined in Peter Schweizer's book, "Throw Them All Out: How Politicians and Their Friends Get Rich Off Insider Stock Tips, Land Deals and Cronyism That Would Send the Rest of Us to Prison."

The book is chock full of examples of self-dealing transactions by high-profile pols like former U.S. House Speakers Nancy Pelosi and Dennis Hastert as well as many other lower-profile members of the House and Senate.

U.S. Sen. Richard Durbin of Illinois, the self-described Mr. Clean himself, was among those who used his access to special information before the bank meltdown in 2008 — first to dump his stock investments before the crash and then later to buy.

In addition to criminalizing stock purchases based on insider information, the proposed legislation would prohibit lawmakers from tipping off friends and family about nonpublic information that could affect stock prices.

Insider trading is a complicated area of law that can be subject to misinterpretation.

In some cases, violations are crystal clear. Say Congressman Jones hears on the QT that a certain company is going to report skyrocketing profits in a week. He buys the stock before the announcement and watches its price go up after the profit news is announced.

But it's a good deal more complicated when members of Congress attend a briefing by the U.S. secretary of the treasury and hear him warn that the economy is about to crater. If members of Congress call their brokers and order them to sell off their portfolios, as some did in 2008, it's not as clear that it's a violation of law.

Obviously, that kind of behavior is distasteful. Clearly, they are taking advantage of their positions. But it's not at all clear that those actions constitute insider trading as defined by law.

Perception, however, is reality, and members of Congress already perceive they are held in low regard by the public. It's good to see them respond to the public's concerns, and there's no question the improved disclosure requirements will help. Whether it gets to the root of the problem remains to be seen.