Final answer:
The completions for the sentences are 'violation', 'void', and 'illegal'. These terms reflect that contracts related to illegal activities are not legally enforceable, as such activities impair obligations of contracts and destabilize the legal and economic systems.
Step-by-step explanation:
The student's question pertains to the enforceability of contracts that involve illegal activities. To complete the sentences:
- Any contract to commit a crime is in violation of a statute and therefore unenforceable.
- A contract to sell illegal drugs in violation of criminal laws is void because it is a crime.
- A contract to smuggle undocumented workers into the United States for an employer is illegal and therefore unenforceable.
These completions reflect the legal principle that contracts based on illegal activities are not enforceable because they impair the obligation of contracts and abridge the privileges or immunities of citizens or deny due process and equal protection of the laws. Furthermore, such activities go against public policy, and the legal system's role is to deter individuals from engaging in them by rendering related contracts unenforceable. This ensures that the legal environment supports the highest and fullest use of property, including the enforcement of valid contracts, which is crucial for economic growth and societal stability.