As principled and long-time libertarians would know, a non-interventionist foreign policy has been a traditional mainstay of libertarian belief. We would feel that foreign conflicts around the world are none of our business, provided they don't affect the sovereignty of our country. After all, leading our own lives (and thus exercising our own self-ownership) is paramount, and this naturally overrides intervening in every overseas trouble spot. In addition, foreign interventionism is probably a primary reason for the emergence of Islamist terrorism against the United States and other Western states. Neo-libertarians who read this piece might disagree with my argument, nevertheless I feel libertarians as a whole should take note of the precise nature of interventionism.
Paleo-libertarians would often believe that the US federal government's intervention in other nations is a direct consequence of the growth of government. This may be true, nevertheless there is one pressing factor which I believe many libertarians ignore. The United States of America 's position as the sole superpower in the world greatly contributes to the existence of foreign interventionism.
The American superpower
Powerful nations have always sought to exert their power and influence over others. The Roman Empire was the 'superpower' of its day, and evidently conquered large areas of the continent of Europe , spreading its language, culture and customs to these areas.
The British Empire was the most successful of the European colonial empires that arose from the Age of Exploration, at the time of the Renaissance. At its height, after the First World War, over 25% of the Earth's surface was under British rule. It remains the largest empire, in terms of land area, in history. As a result of this hegemony, the British were able to spread the English language, common law, the Westminster System  of parliamentary democracy, the Imperial system of weights and measures and British-created sports such as cricket, Association Football, tennis, golf, etc.
Any major power, by definition, seeks to impose influence. To simply HAVE power is to hold control or dominance over something. The USA has used its military power to intervene in numerous nations since 1945, including Korea , the Dominican Republic , Vietnam , Grenada , Beirut , Panama , the Persian Gulf , Somalia , the former Yugoslavia , Iraq and Afghanistan .
In reference to the USA 's cultural influence, most of the world's sovereign states remain touched by some cultural aspect of America . There can't be many people who've never seen The Simpsons, never watched a film starring Arnold Schwarzenegger or never used an operating system created by Microsoft. As a consequence of economic power, the United States has managed to spread aspects of its culture to various parts of the world.
I'm not an expert in geopolitics, nevertheless from my layman's perspective, there will always be countries that rise to predominance over others. In my mind, such a phenomenon arises from human nature and the coercive nature of government. As long as we have governments, countries will seek to control the world.
We all know that government is force. However, it doesn't just initiate force against its citizens. Human beings seldom know how to responsibly handle great amounts of power. Often power 'goes to one's head' and is consistently misused. Humans also have a tendency to threaten, and even bully, those weaker than them. As a result, a stronger and more powerful country would attempt to enforce hegemony over its less powerful neighbours. In the Middle Ages, England sought to conquer Scotland , Wales and Ireland as a consequence of such traits. The USSR was built partly by subduing smaller states, such as Latvia , Lithuania and Estonia . As Lord Acton stated, 'power corrupts, but absolute power corrupts absolutely.'
Stop being the superpower
What I am about to state would be anathema to American neo-conservatives everywhere. The United States should cease from being the world's only superpower. Is this a crazy idea? It's not as crazy as it may seem.
In relation to Islamist terrorism, such an occurrence can possibly be attributed to American meddling in Middle Eastern affairs (despite President George W. Bush stating that they 'hate our freedom'). I've attempted to establish that the natural power created by superpower status has led to foreign intervention. In all likelihood, it is clear that without superpower status, fewer people would have cause to despise the United States , or seek harm against it. Since 9/11, Al Qaeda is known to have attacked only countries that fought against Islamic states, be this the 7/7 London bombings, the Bali bomb or the Madrid bombings. If a hatred of liberal democracy is the root cause of Islamist terrorism, then why hasn't New Zealand , Japan , South Africa , Jamaica or the Republic of Ireland incurred attacks by Islamists? Aren't these countries liberal democracies too?
Really, why does it matter if the USA is not a superpower? The 'worth' of a country cannot generally be calculated solely in terms of its power. China is a country of emerging power in the world, but it has a poor quality of life. As a libertarian, I would only want my country to be a peaceful, prosperous, happy and free society. Exerting power internationally is irrelevant and not conducive to such a goal. In 2005, Luxembourg possessed the highest Gross National Income per capita  in the world. Do many Luxembourgers care whether they are a global superpower or not? Do many Luxembourgers lament at not possessing great power over other nations? I doubt it. Most, I imagine, are relatively content at being a prosperous sovereign state that is secured from outside threat. If the United States is a wealthy, free and secure society, then the concept of being a 'superpower' is a redundant and superfluous one.
The existence of foreign interventionism is deeper than one may believe at first. Intervening in the affairs of others is inherent and intrinsic to being a global superpower. Ultimately, all that libertarians should care about and focus on is the creation of a stable, happy, prosperous and free society in which all are unbound by restraint to exercise their self-ownership. Possessing great power in the scheme of world events is secondary to such a goal.