European (well, mostly British) examples:
Margaret Thatcher would be popular with American posters, and might even be elected to the staff, but would irritate the hell out of half of the Brits here. She'd be forthright but sensible for a few months, then become more and more doctrinaire and divorced form reality until she got ejected from the staff. Then the rest of her membership would become consumed in a mission of revenge on the staff for their "betrayal" (when actually she'd long since ceased to be any use) until she finally descended silence punctuated by wild-eyed alcohol-fuelled rants nobody paid much attention to.
Jacques Chirac would be banned after a few posts for his point-blank refusal to debate in English.
Tony Blair would be superficially popular and convincing, and would be an enormously active poster in all forums on all subjects, but after a while his response of "but I am just plain right" in reply to requests for supporting evidence after having been caught out fabricating such evidence in the War on Terror thread would alienate all but the most gung-ho posters such as
Dubya and
Halle Burton.
He would, however, constantly luck out of getting strikes and other disciplinary actions by somehow managing to capture the mood of the entire board in the first reply to all the major issue threads as they arise.
By comparison
Dubya's responses would be way down on page two or three of the thread, and would be largely one liners of "what Tony said", merged with "God Bless America" and some sabre rattling.
Peter Mandelson would be the oily little tick whose apparent insincerity led everyone to ignore him. Except
TB, because they are firm friends that go back a long way, but they would never both appear on the same thread, instead corresponding entirely via PM.
Rupert Murdoch wouldn't post at all - he'd be trying to buy the board from
Mike &
Jaime.
Silvio Berlusconi would be a loud and omniprescent poster, saying many of the same things as
TB and
Dubya.
AND he'd be trying to buy the board from
Mike &
Jaime (for much less than [p]RupeForever[/b]). And denying that he sent unpleasant and violent fat men in track suits and shiny socks to Savannah by way of persuasion.
Kofi Annan would be trying deperately to stay as a Moderator and be taken seriously, but would make huge gaffes every now and then that undermined his credibility.
Plus, since he never actually issued any strikes or mod notes in any active threads, everyone would wonder why he thought he was so important.
Some posters would also be suspicious of the way he moderated another poster with a similar handle using the same IP address in the War on Terror thread.
Nelson Mandela would be universally respected, despite a youth that involved the active fomentation of virulent flame wars on other boards, albeit in a good cause, and albeit that these boards had draconian and racist moderators. Having had not internet access for many years following successful court action by the now defunct racist debate forum, his membership of this one became in itself a cause for celebration. His measured and constructive posts, though increasingly rare, make him a popular and well respected member.
Gen P Musharraf is an infrequent poster here, and mostly parrots
Dubya,
TB and
SilvioTVStar when he does appear. However, in the Urdu Language forum Pakistan's Debate, he seems to pander to the other extreme. Nobody on

bothers to check there very much. Except
Wertz who occasionally sends him a PM challenging his apparent hypocrisy, which
Gen P ignores.
Osama bin Laden two or three virulent and flagrant rule violations in his first few posts earned him a lifetime ban. However, his fevered rantings on his blog page - www.beardie-weirdo-al-jazeero.org.pk - continue to inspire the odd newbie to enter the board quietly, say a few uncontroversial things to put everyone at their ease, and then competely ruin a thread with an unsubstantiated and offensive outburst, often at the same time as another similar fool does the same thing on another thread. The rants usually contain straight lifts from the bin Laden blog, though it's hard to say whether the shadowy blogger is directly behind them, or the attackers just like his rantings.
Despite the best efforts of
Dubya,
TB,
SilvioTVStar and particuarly
Gen P, who owns the ISP that
Osama is thoght to use, to close his website, he remains at large.