An interesting discussion on what constitutes attempted murder appears today on the blog, Volokh Conspiracy.  Law professor Eugene Volokh writes about a movement within American Christian Dominionism that is calling for imprecatory prayers for John McCain so that Sarah Palin leads the Republican presidential ticket.  At issue, is what constitutes "attempted murder", when the act is impossible to carry out.  David Friedman, a professor at SCU, has written on this topic with an essay, "Impossibility, Subjective Probability, and Punishment for Attempts" which discusses whether voodoo practitioners using imprecatory prayers should be criminally liable.

Prayer as attempted murder?  -- Volokh Conspiracy

Impossibility, Subjective Probability, and Punishment for Attempts -- David Friedman (personal website)