Mir Hossein Mousavi, the reformist candidate challenging Iran’s authorities on the result of last week’s presidential elections, is a masterful tactician who wants to overturn the re-election of his rival, President Mahmud Ahmadinejad, with allegations of a massive conspiracy that he claims cheated him and millions of his supporters. These supporters, identifiable by the color green they have adopted, have taken to the streets in the tens of thousands and on Thursday were to stage a “day of mourning” for what they say is a lost election. This follows a “silent” march through the streets of the capital on Wednesday. To date, at least 10 people – some Iranian sources say 32 – have been killed in clashes.