A.V.Dicey summarised the rule of law (in the UK) under three heads.
Primarily...No man could be punished or lawfully interfered with by the authorities except for breaches of law. In other words, all government actions must be authorised by law.
Secondarily...No man is above the law and everyone, regardless of rank, is subject to the ordinary laws of the land.
Finally...There is no need for a bill of rights because the general principle of the constitution are the result of judicial decisions determining the rights of the private person. (this last point of course is not shared with the American tradition - and since the Human Rights Act 1998, is now rejected here)
{The memorial at Runnymede, pictured above, was built by the American Bar Association - which intends to meet there in 2015 - the 800th anniversary of King John's signing of the Magna Carta at that place}