Liberals across the developed world are very concerned by inequality within the United States, as demonstrated by global interest in the Occupy Wall Street movement. This is peculiar because poverty within the United States is less common, and less severe, than it is in most countries around the world. The US does have a high level of inequality for a developed country, but it is not extreme by global standards Unfortunately, this disproportionate concern for Americans leads to attempts to narrow income inequality that may increase poverty and inequality worldwide.  I’ll explain how.
The US has long been one of the most innovative countries in the world, and exports the technologies it develops everywhere it can. This is, at least in part, due to its relatively cut-throat culture and laissez-faire economic system. Low taxes and ungenerous welfare mean the benefits of working hard, taking risks and making it big, are higher in the US than most other developed countries. More importantly, weaker regulation in the US means incumbents are less protected from competition, and talented people can more easily start new firms and overturn the status quo. Conversely, daring entrepreneurs are less rewarded in countries which redistribute a great deal of wealth to the poor, or build thickets of regulation that unintentionally (or intentionally) slow down disruptive businesses and technologies. While tempering the ravages of the market may on balance improve the welfare of current Americans, doing so is likely to lead to less experimentation in science, equipment, software, art, business models and so on.
Such innovation generates enormous and enduring positive externalities because the successes are copied at low cost across the world and enrich everyone’s lives. Economic theory would predict that coordinating to stimulate more of these costly but invaluable innovations would be a major concern in international diplomacy. But for some reason it is not, and so it is up to individual countries and the people within them to take these risks on behalf of us all.
Miserly social security and weak regulation in America at most harm 0.3 billion people as long as such policies persist; any resulting innovation spillovers help the remaining, poorer 6.7 billion for centuries to come because improvements in technology persist and compound over time. We all continue to benefit from the hard work of those who developed the telephone and prompted the development of an ever-growing number of related products.
This is not to say that the Occupy movement does not have some important points; it is crucial to oppose the US’s many ‘crony capitalist’ policies which enrich the wealthy while also stifling competition and creative destruction.  Nor would the ideal necessarily be a minimal government; there is a prima facie case that government investment in education, R&D, natural-monopoly infrastructure, and so on, can spur technological change. Unfortunately, a higher and higher share of US government spending is going to the opposite: the military, Medicare, Medicaid, unemployment benefits and pensions. These programs are not investments in the future, and generate few if any positive spillovers for future Americans and the rest of the world. And because these programs are funded by taxes on the hard-working and successful, they blunt the incentives to invent things that help the whole of humanity.
Anyone who cares about lowering poverty and inequality, and doesn’t believe that American citizens are dramatically more important than everyone else, should think carefully before encouraging the US to follow the European economic model. If the US were go even further and slip into the sclerotic ‘extractive‘ economic model found in most of the developing world and some of southern Europe, it would be a global catastrophe. Resisting any movement in this direction is one way that heartless US conservatives are inadvertently more compassionate than they look.
Update: Turn out I’m I’m not the first person to notice this problem!
Update 2: Many people below doubt whether the US is more laissez-faire, and whether a laissez-faire model does as a general rule foster innovation. If you doubt these things, at least take away the point that whichever policies you think do stifle innovation, whichever countries they are found in, are much more harmful than they first seem. I will research and write up more on the topic of which broad economic settings lead to the most innovation in the future.
 The effect on wealth inequality is unclear, but the effect on ‘welfare inequality’ is likely to be negative.
 Though perversely, lousy healthcare policies have led to very high prices for medicine in the US, which has driven investments in new procedures and drugs, which have been borrowed by other countries. My guess is that effort probably would have been better directed at other industries.