It long has been our theory that the Monica Lewinsky scandal resulted in the impeachment of President Bill Clinton because everyone could understand it. It was patently sleazy. No subtlety was involved.

Compare that to the finagling that led to the 2008 collapse of the financial markets. Trillions of dollars, millions of jobs and hundreds of thousands of homes were lost. And the average American still has no clue about “credit default swaps.”

Now comes the burgeoning LIBOR scandal, the revelation that for years, British bankers, possibly in collusion with three U.S. banks, manipulated the daily fixing of the London Interbank Offered Rate. This scandal could have cost you — and, indeed, might still be costing you — hundreds, if not thousands, of dollars in higher interest rates on your business, mortgage and consumer credit loans. It might be costing your city and state governments millions of dollars because their bond rates are too low.

The LIBOR scandal could well be criminal. If it is, people should go to prison.

Every day in the City of London, a group of bankers sets borrowing rates in 10 currencies at 15 maturity rates. The most closely watched is the three-month U.S. dollar rate, what banks would pay to borrow from one another at 11 a.m. that day.

Bank-to-bank loans are assumed to be the safest, thus the LIBOR rate (0.4551 percent on Monday) is rock-bottom. But a huge percentage of the world's credit rates are set off this benchmark. With the world awash in $800 trillion of credit, a bank that knows what the LIBOR is going to be can make a lot of money on a very small change.

In a $450 million settlement last month, Barclays, the British bank that is the world's fourth-largest, admitted to British and U.S. regulators that over the past five years, its employees, at times in cooperation with employees at other banks, manipulated the number. Investigators in at least five countries and the European Union are looking into possible involvement by some 20 other banks.

Potential liability runs into the hundreds of billions. Attorneys general and treasurers from three states are investigating how much the scheme cost their investment portfolios. Depending on how far downstream the scandal flows, corporate loans, mortgage loans and credit card loans might have to be adjusted. It could make the fallout from the 2008 financial disaster look like a picnic.

But anyone suing banks for collusion would have a heavy burden of proof. The LIBOR doesn't measure actual transactions, but the arbitrary setting of a trust-based index.

The U.S. Justice Department reportedly is trying to build criminal cases.

Attorney General Eric Holder's Justice Department has not aggressively pursued fraud cases stemming from the 2008 market collapse. Cases are tough to make. Big banks are lawyered up to the eyeballs. They give a lot of money to politicians. Financial regulatory budgets have been cut back and will be cut further if Republicans have their way.

It's a question of priorities — when you send 93 investigators and lawyers after Roger Clemens for lying to Congress about his use of performance-enhancing drugs, who's got time for epic financial fraud?