At the beginning of politics there was a free market for force. Anyone who could round up a posse had his own little army that could provide protection in exchange for tribute - of food, gold, women, whatever. The successful posses became states, and as more land and people came under their protection they started establishing bureaucracies to manage it all.
Over the years many of these groups failed.
Nowadays force is controlled by a cartel known as the UN of about 200 of these groups who call themselves countries, have mostly agreed upon territories for their control, and support each other if any nascent group tries to challenge their monopoly. They've diversified somewhat from their original purposes - though they still exact tribute, they now offer more services in return.
Now, this is my critique of libertarianism:
We view the original state of nature as pure freedom. These groups formed corporations to provide security to their customers in exchange for tribute - payment - which was given to their shareholders: the warriors or nobility. Doesn't history then prove that over the course of time a state of infinite competition settles into one of multiple monopolies which band together to stamp out potential challengers in their market? This entirely disproves libertarianism's main argument that infinite competition will provide infinite freedom.