Many political documents are nothing more than statements of a moment. They're outdated almost as quickly as a daily newspaper.

Consider the ridiculous Post Huron statement, drafted 50 years ago by the far-left Students for a Democratic Society. "We are people of this generation, bred in at least modest comfort, housed now in universities, looking uncomfortably to the world we inherit," it begins. Well, since those students are now retirees, mostly living in "modest comfort" on Social Security, the rest of the statement is rendered meaningless to today's world.

Or there's the 1972 Anti-Ballistic Missile treaty, signed by the U.S. and the Soviet Union. President George W. Bush finally put that agreement to rest in 2002, more than a decade after the U.S.S.R. had disappeared.

As Americans get set to celebrate July Fourth, it's worth asking: Is the same thing true of the Declaration of Independence? It may be seen as nothing more than a list of complaints filed against a tyrannical monarch by a bunch of white landowners wearing wigs. Since George III and the colonists are long dead, their words no longer matter, right?

Wrong.

Indeed, the Declaration charged the king with 30 offenses, some legal and some matters of policy. Thus the colonists announced they were "absolved from all allegiance to the British crown and that all political connection between them and the state of Great Britain is, and ought to be, totally dissolved."

But the brilliance of the document is that the founders didn't stop there. The Declaration's greater meaning was as a statement of the conditions of legitimate political authority and the proper ends of government. It proclaimed that political rule would, from then on, reside in the sovereignty of the people. "If the American Revolution had produced nothing but the Declaration of Independence," wrote the great historian Samuel Eliot Morrison, "it would have been worthwhile."

The ringing phrases of the document's famous second paragraph are a powerful synthesis of American constitutional and republican government theories. All men have a right to liberty as they are by nature equal. None are naturally superior, and deserve to rule, or inferior, and deserve to be ruled.

Because men are endowed with these rights, the rights are unalienable, which means that they cannot be given up or taken away. And because individuals equally possess these rights, governments derive their just powers from the consent of those governed. Government's purpose is to secure these fundamental rights. Although prudence tells us that governments should not be changed for trivial reasons, the people retain the right to alter or abolish government when it becomes destructive of these ends.

To be fair, the United States hasn't always lived up to the ideals of the Declaration. At the time it was signed, free blacks enjoyed citizenship in several states – at least five, according to Supreme Court Justice Benjamin Curtis, who researched the subject for his dissent in the 1857 Dred Scott decision.

But over the decades, the rights of blacks eroded. It took the 1860 election of Abraham Lincoln and a massive Civil War finally to end slavery and begin delivering the promises of the Declaration. And there was more to come.

"When the architects of our republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall heir," is how Martin Luther King, Jr. put it in his "I Have a Dream" speech. That note has, thankfully, been completely redeemed.

The Declaration will always apply, because its appeal was not to any conventional law or political contract but to the equal rights possessed by all men and "the separate and equal station to which the Laws of Nature and of Nature's God" entitled them.

An aged John Adams was asked to prepare a statement on the 50th anniversary of the Declaration of Independence, and he delivered two words that still convey our great hope every Fourth of July: "Independence Forever."

May the ringing phrases of the Declaration of Independence always speak to all those who strive for liberty and seek to vindicate the principles of self-government.