SAN FRANCISCO (MarketWatch) -- They say those who cannot learn from history are doomed to repeat it. But in Internet time?

The testimony of a major hedge fund trader Wednesday in hearings on abusive commodities speculation sent a chilling message about our attempts to clean up Wall Street in the wake of the financial scandal. Not because the trader, John Arnold, is among the most successful energy traders in the country, and has important things to say. Not because he came out in favor of limits on commodities trading, which goes against what most of the industry wants. Not because everything he said made sense.

It was because in his bio is a stark reminder of what happens when we collectively ignore a major scandal and move on to the next bull market. Arnold, now managing partner of the $5 billion Centaurus Advisors hedge fund had worked for Enron Corp. back in the day.

First things first; Arnold was never tainted with any of the scandal that brought down the energy trading powerhouse at the turn of the decade. His Houston-based energy trading firm is among the biggest players in the industry, which is probably why he was called to testify. And he came out in support of limits on some commodities trading, arguing that it made the business more transparent and efficient. See full story.

But his history with Enron makes his comments even more significant, because he's lived on the wild side of energy commodities trading. And just the mention of Ken Lay and Jeffrey Skilling's former company should be enough to make anybody who lived through the scandal in 2001 cringe with embarrassment when looking at what we failed to do in this country to prevent another one.

The disastrous and ultimately useless Sarbanes-Oxley law on accounting disclosure was rushed through. A handful of CEOs were tossed in country club jails. And the usual bunk about greater corporate governance was debated at conferences.

Yet only seven years after Enron went down in a flaming pile of management hubris and false accounting -- taking corporate America's reputation with it -- small investors and savers found themselves again at the mercy of a Wall Street-induced scandal, this time one that would take down the world economy.

No wonder Timothy "Come on, guys" Geithner, our usually placid Treasury Secretary, exploded in a profanity-laced tirade recently at a meeting with financial regulators. Now that the major bleeding has stopped in New York, banks and bankers want to get back to business. And regulators of those banks and bankers want to keep their turf. So the old battles have started up again in Washington and the prospect of major financial overhaul grows dimmer by the day. Perhaps sometime after the health-care issue gets addressed, right?

There have been a lot of batty ideas coming out of Washington in the first few months of the Obama Administration with regards to Wall Street. The idea of taxing bonuses at 90% comes to mind. But the core idea that something must be done to rein in abusive trading and risk-taking, and the compensation impetus behind them, is still something that must get done.

The time to push through some sort of overhaul is still now, while the administration is young and can wield influence. FDR pulled it off during the Great Depression, and it changed Wall Street for 70 years. Nothing of that magnitude appears headed anywhere now.

Sure, commodities regulators are considering imposing trading limits. Bans on certain types of electronic trading, called flash trading, as well as so-called "naked" shorting of stocks, are still in play. But the horse is already out of the barn on most of this stuff, and Wall Street will just find another angle.

The consensus for change has evaporated in New York, where bankers await a return of mergers and acquisitions and the rising stock market masks the pain of a global collapse in confidence in financial services that has yet to have its first anniversary. In Washington, it is also slipping. That's why John Arnold's testimony is important.

It's now a world where massive, society-breaking financial scandals happen not once a generation, but once every presidential election cycle or two. Yet they are tossed aside the next time stocks rise and the job market picks up. In such a world, the term Enron serves as a cold, dark monument to our inability to pay attention to history long enough to protect ourselves from the next scandal -- probably brewing right now.