Cliff May

President Bush was under no illusions about the threat a nuclear-armed, militant Islamist regime in Tehran would pose. But during two terms in the White House, he took no serious steps to prevent this capability from steadily developing.

President Obama also does not appear to be under any illusions. "Iran's development of a nuclear weapon, I believe, is unacceptable," he said during his first post-election press conference.

The Obama administration's initial response was to pursue "direct diplomatic engagement" with Iran. But Secretary of State Hillary Clinton, traveling in the Middle East this week, reportedly told an Arab foreign minister that it now seems "very doubtful" that such an approach will succeed. Significant pressure will be required to persuade Iran's ruling mullahs to give up their nuclear ambitions -- not to mention their support of terrorist groups abroad and their egregious human rights violations at home.

But, short of military action, what leverage can Obama exert? He could cut off the flow of gasoline to Iran. Indeed, this is an approach for which Obama has expressed support on at least three occasions. "If we can prevent them from importing the gasoline that they need," he said during a campaign debate in October, "that starts changing their cost-benefit analysis. That starts putting the squeeze on them."

Iran is one of the world's leading oil exporters but it has not invested much in oil refineries -- it has spent its money on nuclear development instead. As a result, Iran must import almost half the gasoline it consumes. Just a few companies have been filling its tanks. The most important of them is Vitol, a Swiss firm.

Last Friday, a bipartisan group of House members -- Howard Berman, Brad Sherman, Ileana Ros-Lehtinen, Robert Wexler, Mark Kirk, Rob Andrews and Edward Royce -- sent a letter to Energy Secretary Steven Chu, asking him to reconsider a federal government contract awarded to Vitol in January, just days before the Bush administration left office.

They noted that Vitol has a checkered history, for example, pleading guilty, in 2007, "to grand larceny in New York state court in connection with kickbacks to the Iraqi government" in the Oil-for-Food scandal orchestrated by Saddam Hussein. That alone, the congressmen wrote, "could provide sufficient grounds for debarment from federal contracting."

Cliff May

Clifford D. May is the President of the Foundation for the Defense of Democracies.