This is a simple point, but important. All capitalist systems or systems based on markets – or indeed human society of any sort – require law and order and ultimately force and coercion to back up the law and the enforcement of the law. That is why a “pure” laissez faire society or economy in the strict sense is impossible, because it would reduce to a system without law, rules or the enforcement of law. It would be a literal anarchy with no rules. At a minimum, there needs to be respect for the law, property rights and the enforcement of non-fraudulent contracts when one party violates the contract or breaches a contract.
Even Rothbardianism, the most extreme laissez faire system dreamed up by libertarians, has as its foundation a private law code and private justice system, which would still ultimately require coercion and force to enforce and maintain that order. The only difference between a state-based system and a Rothbardian system is that in the latter the coercion and force is done by competing private protection agencies and a private justice system.
Obviously to decide what institutions (such as government) and practices are necessary, defensible and moral in any society in a prescriptive sense requires an ethical theory. At that point, debates about the ultimate basis of how a society enforces its laws and how and what laws it passes collapse into debates about philosophy of ethics.