Interestingly, those leaders that supported Bush in the leadup to the war in Iraq have all withstood challenges and succeeded, though Italy is hanging by a thread. The Paris-Berlin Axis, on the other hand, is in danger of collapse.
This has nothing to do with the EU referendum, per se, just an interesting side note.
Putin, Chirac, and Schroeder are all still very much alive, and the only one in danger of being ousted before the end of the year is Schroeder, and that's only because of his own suicidal choice.
Aznar on the other hand is already out, and Berlusconi, despite trying his damndest to hang on to every last moment of power, is looking at uphill in early 2006.