Hooman Majd, author of the recent book "The Ayatollah Begs to Differ," spoke recently of the meeting with American scholars that Ahmadinejad held during his New York visit. Reporters were told it was off the record but TV cameras were present. They were there to provide footage for domestic consumption – the president as international figure discussing important issues with Western scholars.

This is ironic. In America Ahmadinejad is popularly regarded as a crazed religious fanatic in pursuit of a nuclear weapon which he will not hesitate to use to wipe Israel off the face of the map. This is a caricature from a horror cartoon but unfortunately is taken seriously enough in some U.S. circles to influence the foreign policy debate. Senior advisers to the Republican presidential candidate Sen. John McCain are quite ready to contemplate the use of military force to prevent Iran obtaining a nuclear weapon.

This would be disastrous for the United States. For the sake of delaying an Iranian nuke for a year or two it would lose popular support among the most pro-American people in the region, it would isolate itself internationally even more than after the Iraq invasion and probably cement formal anti-American alliances revolving around Iran, Russia, and Venezuela. Not least it would likely precipitate Iranian counteractions against the oil supplies flowing through the Strait of Hormuz and increased violence and instability in Iraq, Lebanon, and Palestine fomented by Iran's proxies.

And all this because of a man who would not even have his finger on Iran's nuclear trigger should it get one. A sensible U.S. policy needs to take account of the political realities within Iran. One of those realities is that Ahmadinejad faces considerable criticism both for his economically disastrous domestic policies and for his international posturing. And that criticism encompasses both moderate reformers in the camp of former President Mohammad Khatami and disenchanted conservatives, some at the highest political levels.

For the United States the alternative to the military approach is diplomacy, proposed by Sen. Barack Obama the Democratic presidential candidate. But this approach too needs to be exercised with caution and an informed understanding of internal Iranian politics. Hooman Majd relates the advice to Obama that he heard from both Iranian reformers and conservatives opposed to Ahmadinejad. If Obama wins, they said, he should do nothing on Iran before the 2009 elections. To start talks before that would boost Ahmadinejad's domestic support.

There's a time for talk and a time for action. And in smart diplomacy there can also be a time for neither acting nor talking.