American companies are already banned from investments in Iran - but not so, European ones. Thanks to former Sen. Al D'Amato, a 1996 law imposes sanctions on foreign companies that invest in either Libya or Iran - but President Bush, like Bill Clinton, has consistently exercised the law's national-security loophole to waive it.
But the Europeans can't stop us from selling off the stock of companies like Shell, Repsol or Total that do business with Iran. The disinvestment drive is only a few months old, but it has already pushed Repsol, a Spanish company, and Shell, a Dutch firm, to reconsider their Iranian investments.
It's no sure thing - but disinvestment is a safe way to weaken the Iranian regime, and one we don't need approval from the United Nations - or Washington - to execute.