Jeffrey Goldberg. Photographer: Steve Voss/Bloomberg
Jeffrey Goldberg. Photographer: Steve Voss/Bloomberg

So it seems that Iranian President Hassan Rohani, who has undertaken a charm offensive at the United Nations this week, can't bring himself to charm the one person he actually needs to charm, the man who has placed crippling sanctions on Iran's economy.

President Barack Obama was willing to shake hands with Rohani on the sidelines of the UN General Assembly today, but the Iranian president wasn't ready for such a dramatic encounter -- even an unphotographed one.

This doesn't suggest xenophobia on Rohani's part, but weakness. He's obviously afraid of being seen as overly conciliatory to the Great Satan by hardliners in his own government. Which, of course, means that Iran may not be ready for the conversation it claims to want to have about its nuclear program.

As I argued earlier today, I don't think the Iranians are serious about giving up their pursuit of atomic weapons. What they are serious about is trying to get the U.S. to ease sanctions without having to give up crucial components of their nuclear program.

Obama's critics in the U.S. are arguing that his outreach to Rohani -- his willingness to exchange a handshake and small talk -- makes him look weak. This is silly. Diplomacy doesn't equal weakness. Weakness equals weakness. Obama put Rohani on the defensive by offering this informal encounter.

I'm worried that the Obama administration could become overly excited by an Iran breakthrough, but what Obama did today wasn't a sign of gullibility or desperation. He was simply testing the sincerity of Iran's charm offensive. And the charm offensive did not pass muster.

(Jeffrey Goldberg is a Bloomberg View columnist. Follow him on Twitter.)