Why might a contract be deemed unenforceable due to legality?

A contract can be deemed unenforceable due to legality primarily if it involves illegal activities. The legal principle behind this is that contracts are intended to enforce equitable agreements that abide by the law. Therefore, any contract that requires one party to engage in illegal actions or that is formed for an illegal purpose violates public policy and is not enforceable in a court of law. This protects the integrity of the legal system and ensures that individuals or businesses cannot seek legal recourse for agreements that contravene established laws.

While the other factors mentioned, such as the need for a contract to be in writing, the potential to exceed maximum payment terms, or a lack of mutual agreement, can lead to issues regarding enforceability, none of these directly address the core principle of legality. Instead, they focus on procedural or structural aspects of the contract, rather than its fundamental compliance with the law, which is the crux of why a contract might be deemed unenforceable due to legality.