My understanding of American history is that the country was founded on the principle that all people have inalienable rights to life, liberty, and the pursuit of happiness that cannot be abrogated without due process of law. This was in reaction to the historic fact that despotic kings and governors with unlimited power have been notorious for having people they don't like either detained at their pleasure, or even tortured or killed. A well-known historical precedent for imposing checks and limits on the power of kings is of course Magna Carta. King John of England was forced to sign this document in which he acknowledged that he was subject to the rule of law and could not arbitrarily violate the rights of his subjects.
Although the American Constitution was designed to place strict limits on the powers of government, these limits have been progressively eroded or ignored altogether by a succession of modern presidents from both the major parties. A glaring example of such disregard in recent times is the disgraceful conduct of George W. Bush in having people detained for years at Guantanamo Bay without any charges and without trial, in open defiance of international law. President Obama has continued this tradition of disregarding the constitution by enacting laws that enable the President to not only have people detained without trial at will on the mere suspicion of terrorism, but to actually have people killed, again on mere suspicion without charges or trial. This has been described as an "Alice in Wonderland" style of justice in which people are sentenced first and then tried later.
King John, Obama's forebear
Military given go-ahead to detain US terrorist suspects without trial