The inauguration of Mahmoud Ahmadinejad may have placed foreign leaders in a dilemma over diplomatic protocol but it makes little practical difference to how they will negotiate with Iran.

President Obama’s offer of direct nuclear negotiations was made long before the current crisis, when there seemed to be little doubt that Mr Ahmadinejad would be re-elected. And under Iran’s complex theocratic constitution, it is highly unlikely that Mr Ahmadinejad would even be involved in any such talks.

This is one of those paradoxes almost unique to Iran. While Mr Ahmadinejad is the Iranian who struts across the global stage speaking loudly about nuclear rights and wiping out Israel, he has no responsibility for either foreign or nuclear policy: that is the province of the Supreme Leader.

Even if Mir Hossein Mousavi had won the election, he would have been unable to push for greater engagement with the West unless Ayatollah Ali Khamenei agreed.

The way that the Supreme Leader threw his support behind Mr Ahmadinejad with an unprecedented public endorsement, and his role in the brutal suppression of post-election protests, does not bode well for engagement.

But unless that window closes, there is little to be gained in taking an aggressive stance on Mr Ahmadinejad’s legitimacy.

Britain defended the presence of its envoy at his inauguration, saying that the pressing need was to keep channels open on the nuclear issue as well as the “very concerning” human rights situation.

Reactions are also complicated by the fact that while the election results were clearly fraudulent, nobody knows who actually won. Several Western intelligence agencies believe that Mr Ahmadinejad might well have squeaked in, his tiny majority obscured by the fraud in engineering a landslide.

Robert Gibbs, the White House spokesman, reflected the confusion when he withdrew his description of Mr Ahmadinejad as Iran’s “elected leader” saying: “That’s not for me to pass judgment on.”

Times Recommends

• No apology for Germany’s own Nazi victims
• Intricate web of fear and hope tying down deal
• Victims remembered a year after Mumbai attacks