The first sentence of the second paragraph of the Declaration of Independence reads as follows:

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

This set the tone and framework for a new country that would be like none other in history when the thirteen colonies declared their independence on July 4, 1776 from Great Britain.  In those seven words, a tone was set that unfortunately opened up possibilities with detrimental unintended consequences.

"Pursuit of life, liberty and happiness" should have read, "the pursuit of truth, character, virtue and charity."  Happiness is totally subjective, based primarily on egoism and individualism, whereas truth, virtue, and charity all focus on honesty and doing the right thing toward others rather than oneself.  Character focuses on sacrifice rather than acquisition and accumulation. 

The self in its pursuit of prosperity and pleasure is what the "pursuit of happiness" in the Declaration of Independence has come to mean.  "Life, liberty and the pursuit of Happiness" are natural derivatives that would automatically occur based on the way this all-important sentence should have been written, because it would have included this missing moral dimension as the leading objective for the new republic.

The Founding Fathers created the most advanced political document in history that was highly influenced by Enlightenment philosophers, most notably Locke, Montesquieu, and Rousseau, who, among many others, created an intellectual revolution and changed the world with its focus on individualism and freedom.  But, unfortunately, what they left out, "throwing the baby out with the bathwater," if you will, in overthrowing the old hierarchies of authority of the political and religious orders at the time was forgetting to combine individuality and freedom from authority with a moral order and code of conduct.

The Age of Reason, as the Enlightenment is sometimes called, gave us rationalism but neglected spiritualism, which goes a long way in explaining why today's culture is overwhelmingly secular.  And this is where Jefferson, Madison, Franklin, et al. unwittingly went astray.

Although the Founding Fathers were extremely religious and were all self-declared Christians or deists, the structure of "pursuit of happiness" untethered to the Christian moral foundation they believed in has been left wide open to interpretation and in turn has led to the self-absorbed culture of greed we have today.  What is the difference between a man who has reached the pinnacle of his profession and a drug addict or alcoholic?  Each pursued his individual happiness and succeeded.  The only problem is that one path in pursuing personal happiness is deemed socially acceptable, while the other is not.

The United States, along with most of the other Western democracies, has succumbed to the tyranny of the self because of this lack of a foundational morality and code of conduct.  Not only has it led to the rampant egoism we see every day in every walk of life, but it's also contributed to unbridled materialism.  Without any moral restraints on the "pursuit of happiness" or any universal standards of character, virtue, and truth, we are witnessing what happens when maximizing material comfort and pleasure becomes the highest objective and value in the land.  Liberalism has led the way in tearing down what restraints once existed, although conservatives can be just as culpable, because we've also bought into these values as well.

To defend the Founders, they couldn't have foreseen the explosion in vices facilitated by both the money-making appeal of those vices and modern technology.  But this is why the Declaration of Independence needed to be more specific about the timelessness of biblical morality: because biblical morality always stands the test of time.