One of the pleasures of living in America is getting to argue about rights. In the last week, we've all had a rousing time debating the right to keep and bear arms. Americans can hardly talk about political issues without invoking these fundamental prerogatives.

The right to life and the right to liberty are common assumptions around the world. But only America was founded on a right that, even today, sounds eccentric: the right to the pursuit of happiness.

The delegates in Philadelphia who approved the Declaration of Independence had a long list of complaints about King George III. They excoriated him for maintaining a standing army, dissolving elected assemblies, imposing taxes without the consent of the taxpayers, and sending out "swarms of officers to harass our people, and eat out their substance."

Those are all specific, tangible abuses understandable to anyone. But the idea that the king was somehow interfering with Americans' propensity to chase after bliss was a novel one. No more. One of the notable changes in the world in recent decades is the spread of freedom, including the freedom of each person to pursue happiness as he or she conceives it.

Letting people do that, it turns out, actually makes them content. This may sound like the most incontestable of truisms, but it's not.

Some science suggests that happiness is essentially a fixed commodity. It may rise or fall sharply because of events - getting a raise, breaking a leg - but over the long run, people adapt to those experiences and revert to their natural level of satisfaction (or melancholy).

Scratch that theory. According to a recent global survey, happiness is not only variable but on the rise in most of the world.

Two things, it appears, are needed to increase the supply of happiness: freedom and money. As it happens, a substantial amount of freedom is crucial to the creation of wealth. There is no such thing as a rich totalitarian country, as even the onetime totalitarians in Beijing finally realized. So in a very real sense, freedom is the key to happiness.

The survey, by the Institute for Social Research at the University of Michigan, asked people in 97 countries two simple questions: "Taking all things together, would you say you are very happy, rather happy, not very happy, or not at all happy?" And, "All things considered, how satisfied are you with your life as a whole these days?"

Researchers found that among the 52 countries where the poll has been done over the last couple of decades, the percentage of people giving upbeat answers rose in 40. Among the places where smiles have been spreading are such developing countries as China and India, which have grown freer as well as more prosperous.

The same with much of the advanced world, including the United States, France, Canada, Denmark and Japan. Only four countries (Austria, Belgium, Britain and Germany) have gotten less happy since the pre-1981 era. They are all free as well as rich, which suggests that those two factors are necessary but not sufficient.

Still, if money can't buy happiness, it certainly makes misery easier to bear. Some of us might rather be a depressed Brit than a sunny Sudanese.

The Germans also might take a more chipper view of their fortunes were they to consider, say, Zimbabweans, the unhappiest people on the planet. Small wonder, since they live under a psychotic tyrant who has wrecked the economy, inflicting hyperinflation and mass hunger.

The 18th-century English writer Samuel Johnson wrote, "How small, of all that human hearts endure,/ That part which laws or kings can cause or cure." Those who wrote the Declaration of Independence, by contrast, understood that if you want to be happy, it helps to have a decent government and a free society. As it happened, they did want themselves and their descendants to be happy. They also created a pretty good model for any country that wants to be.

/steve_chapman. Contact him at schapman@tribune.com.