Why did Nancy Pelosi refuse to allow a vote that could have resulted in the bringing of more US oil to the US market and a consequent lowering of the price of gas? 

Michelle Malkin supplies the answer:

As reported on dontgomovement.com, Speaker Pelosi bought between $50,000 and $100,000 worth of stock in [T. Boone] Pickens’ CLNE Corp. in May 2007 on the day of the initial public offering:

"She, and other investors, stand to gain a substantial return on their investment if gasoline prices stay high, and municipal, state and even the Federal governments start using natural gas as their primary fuel source. If gasoline prices fall? Alternative fuels and the cost to convert fleets over to them become less and less attractive."

CLNE also happens to be the sponsor of Proposition 10, a ballot initiative in Pelosi’s home state of California to dole out a combined $10 billion in state and federal funds for renewable energy incentives – namely, natural gas and wind.

Follow the money. Or, to put it in economist’s terms as energy analyst Kenneth Medlock III did in an interview with The Dallas Morning News about the Pickens multibillion dollar wind farm investment: "A lot of what he’s trying to do is add value to a stranded asset he’s obviously got millions of dollars on the line."

And so, potentially, does the Democratic Speaker of the House – all the while wagging her finger at the financial motivation of others.