Salary of members of the United States Congress: $174,000.

Average annual Civil Service Retirement System benefits for retired members as of 2007: $63,696.

But the profits they can make by trading on inside information?

Priceless.

Think you're a clever investor? Well I have news for you, Fool -- you have nothing on the stock market wizards who work for the United States Congress.

Don't feel bad. According to research published by economist Alan Ziobrowski, most individual investors underperform the S&P 500 by about 1.4% per year. In contrast, sitting U.S. senators beat the market by an average of 12 percentage points per year.

That's better than the (still impressive) 6% outperformance recorded by members of the U.S. House of Representatives, which in turn matches the surprising prescience of corporate insiders trading their own company's stock (also 6%.) Fact is, members of the U.S. Senate, on average, often beat even the venerable Oracle of Omaha. Warren Buffett's record at the helm of Berkshire Hathaway (NYSE: BRK-B) has amounted to a mere 10.8% annual outperformance of the S&P.

How do they do it? It could be that the U.S. Congress is the greatest amalgamation of investing minds ever assembled since the creation of Wall Street. That could be the answer. But recent investigations by The Wall Street Journal and 60 Minutes suggest another possibility: that members of Congress are getting rich quick on the backs of their own constituents, using their positions to wrangle allotments of IPO shares in Visa (NYSE: V), trading in and out of financial powerhouses like General Electric (NYSE: GE) and Citigroup (NYSE: C), and snapping up shares of solar companies such as SunPower (Nasdaq: SPWRA) ahead of votes to subsidize renewable energy.

We've detailed this story in multiple columns over the years. (Read a few of them here, here, and here.) But a picture's worth a thousand shares of insider-traded stock. So we thought we'd sketch out for you a few facts about what's rotten in the District of Columbia, and about what investors like you and I are doing to clean up this mess. Take a look.

Why you should care
In the words of Motley Fool co-founder Tom Gardner: "Our elected officials owe it to their constituents, and our country owes it to the world, to demonstrate that insider dealing is not what American capitalism and democracy is all about. The mere appearance of cronyism can create a major taint on our reputation."

I second that emotion. Do you? Then join the Foolish fight for passage of House Resolution 1148, the "Stop Trading on Congressional Knowledge (STOCK) Act." Email us at [email protected] and tell us you want to see Congress clean up its act. We'll keep you updated on all the Fool's efforts to get this law passed.