Barack Obama is waving his arms. The crowd is cheering. … I see Barack Obama, one minute smiling, the people crying his name. I see Barack Obama grab his chest and his eyes widen and his mouth opens, and the crowd screams as Barack Obama, black candidate for the presidency of the United States of America, falls to the ground, dead, an assassin's bullet inside him.H/T Mark Steyn
Mark Steyn mentions numerous examples of leftists advocating the assassination of President Bush. To those examples I will add Bill Maher's explanation of why the world would be better off if terrorists killed Dick Cheney and Fox Network's "Family Guy's" frequent "jokes" about the assassination of Bush, Cheney and others.
I can only conclude that the left wants to rally its followers to commit violence. The Obama assassination fantasy is meant to further that goal, as leftist readers are supposed to become outraged and commit violence of their own choosing in retaliation. The same people who want to see Bush assassinated are also hoping to see Obama assassinated, but for different reasons. The left is obsessed with the concept of political violence - even if it is their own candidates that are being assassinated.
Leftists favor assassination for the same reason they favor socialism. Both of these concepts promote chaos and destruction. The left desires the destruction of the American political system. The constant cycle of assassination and reprisal that the left craves will serve that purpose, just as greater socialist controls will serve the purpose of wrecking the economy.
In reality, the only real possibility for an Obama assassination will occur if Obama names Hillary to be his running mate - in which case Obama will be killed as soon as he takes office, after which his death will be ruled a suicide by the official inquest.