Here's a great documentary on Monsanto. It highlights some of the major problems with this corporation. Also, check out the story of Percy Schmeiser, one of the cases of injustice that eventually convinced me that corporations are not consonant with a libertarian society.
Monsanto does not fully compete in the market, but rather uses privilege to gain unfair advantages against competitors. Monsanto is not a person; it is a corporation, a fictional entity that has existence only as a convenient legal abstraction. It was created by the government; in other words, certain people were given the privilege to use an abstraction of legal rules to do business in ways they were not willing to do as individuals.
Legally, Monsanto is actually a person, and that it has inherent rights and protections under the Constitution. Current American case law has resolved this matter as such (although the pedigree is dubious). Much of Monsanto's power derives from its use of its 1st Amendment right to free speech by contributing to campaigns (while simultaneously preventing free speech by its competitors) and 4th Amendment protections from unreasonable searches pursuant to health and safety regulations. But Monsanto is an "it", a collection of assets and contracts given entity status. If it is a person, it is a peculiar type: it has no conscience or will, no children or parents, the ability to spin off parts of itself or absorb other "persons", different laws applying to it than to us (corporate codes). Why are we compelled to treat this impersonal entity called Monsanto with any sort of deference, preference, or even justice?
Living, breathing people are more important than impersonal entities, organizations, etc. Individual interests come before their agendas. The corporations has gotten away with an enormous theft: our legal personality to exercise rights and responsibilities as human beings. Monsanto's crimes would have been severely punished if it were a person that could be locked up or executed.
Still we are not left without recourse. If we don't want Monsanto to exist - if we feel they are a menace and a threat to our lives - we don't have to content ourselves with fining, regulating, or otherwise sanctioning that impersonal collection of assets and contracts that wields so much power in our world. We can kill it.
There is legal precedent in this country for the corporate death sentence - in other words, for revoking the charter of incorporation. The history of resistance against corporations is long, with charters revoked by state legislatures and court decisions for violations of the public peace, health, and sovereignty. Corporations do not have a right to do business.
Incorporation can and should be revoked when its behavior shows it to be unsuitable to a free society of responsible individuals. The fact that charter revocation is not pursued more often is one clue to who is really in charge of this society. In the end, it's not corporations who are the problem, since they don't really exist except in our minds - it is the corporatists, those recipients of privilege who work hand in glove with the government to create an unequal playing field for people who have the capital.
UPDATE: I left a comment on this Marginal Revolution post that's along the same lines as the above thoughts:
Read this articleWenar is certainly on to something, and a lot of what I see in the comments are mere dismissals of an inconvenient fact.
Being an anarchist, I'm not big on any laws to solve these problems. But if we're going to use the state to advance justice (good luck with that) I'd rather see corporate charters dissolved for complicity with criminal regimes. Who are you going to distribute the proceeds of the lawsuit to? These people have no property rights as we understand them, so they will not be compensated for the theft. Rather, let's attack the true cause of this exploitation: the corporate form, which allows for the mobilization of trafficking in goods of dubious origin on a scale no smuggler could ever achieve. Incorporation is a privilege, and we don't have to extend it to entities that help foreign thugs oppress.
And let's remember that, while there are plenty of thieving thugs in the world, it is largely U.S. trade and foreign policy that helps them maintain power and stabilize their export markets. The WTO, through their managed trade agreements that favor corporate interests, undermine the ability of native peoples to control their own economies. Free trade is better, of course, but we can all agree that we don't have that now. This is all to corroborate Wenar's point that the underlying rules governing the market determine how it will allocate resources and wealth - rules like property rights, legal systems, government prerogatives, etc.
Markets are just a tool, an impersonal phenomenon; they can be used for many different ends, depending on how you set the ground rules. Look at China. The WTO manipulates these rules to ensure certain market outcomes, and its supporters are complicit in the crimes of its members.