If it were done when 't is done, then 't were well
It were done quickly: if the assassination
Could trammel up the consequence, and catch
With his surcease success; that but this blow
Might be the be-all and the end-all here,
But here, upon this bank and shoal of time,
We 'ld jump the life to come. But in these cases
We still have judgment here; that we but teach
Bloody instructions, which being taught, return
To plague the inventor: this even-handed justice
Commends the ingredients of our poison'd chalice
To our own lips.
-- William Shakespeare (1564-1616), Macbeth
-- Act i, Sc. 7
