While having the usual discussion about Lord Acton - he said "power tends to corrupt and absolute power corrupts absolutely - I looked up his notable quotations and found an absolutely splendid one:
The one pervading evil of democracy is the tyranny of the majority, or rather of that party, not always the majority, that succeeds, by force or fraud, in carrying elections.It comes from his essay The History of Freedom in Antiquity.
Lovely assortment of Acton essays here.