U.S. House Speaker Nancy Pelosi, seen by many on the American right as a business-hating socialist, proved over the weekend that she has more than a passing interest in free markets.

It all started with a Wall Street Journal article, published Friday, that alleged that Pelosi and her husband had invested between $50,000 and $100,000 in shares of Clean Energy Fuels, the Texas company founded by oil man T. Boone Pickens that sells compressed and liquefied natural gas as an alternative transportation fuel. By the end of last year, the value of her investment had risen to between $100,000 and $250,000, according the Journal.

The report caused a stir. Pelosi, the most powerful Democrat in Congress, has expressed support for national policies that promote the increased use of natural gas. Critics rightly screamed conflict of interest, even if the investment doesn’t violate House ethics rules.

In response, Pelosi, appearing on Sunday on the popular current affairs TV program “Meet the Press,” defended her investment decision. She retorted that it’s a small portion of her investment portfolio—less than 0.3 percent she claimed—that it was part of an “entrepreneurial package” that she had enrolled in, and that she has supported alternative energy long before the stock purchase.

But those excuses don’t fly. While Pelosi undoubtedly supports the expansion of natural gas usage because of other reasons than her investment, the marriage certainly stinks. It damages her authority. It provides fodder for the pro-Big Oil, anti-alternative energy crowd. It may even unconsciously affect her decision-making.

Does she have an ulterior motive to her clean energy policies? we can now legitimately ask.

Pelosi should find a way to make her investment ties to alternative energy less direct, for example through a mutual fund or, even better, through a blind trust. If journalists are expected to avoid conflicts of interest, like owning shares of a company we write about, a Speaker of the House should be held to a higher standard.