In the United States, an unusual type of unenforceable contract is a personal employment contract to work as a spy or secret agent. This is due to the fact that the secrecy of the contract itself is a condition of the contract (in order to preserve a plausible negation). If the spy then sues the government over issues such as salary or social benefits, the spy has breached the contract by revealing its existence. It is therefore unenforceable for this reason, as is public policy of maintaining national security (since an angry agent could attempt to reveal all the secrets of the government during his pursuit).  Other types of non-binding employment contracts include contracts that commit to working for less than the minimum wage and the loss of workers` right to compensation in cases where work compensation is due. Even then, defenses against equity lawsuits (such as Laches, Bona Fide`s buyer`s rule, or impure hands) may be an obstacle to a given performance. Contracts are promises that the law will enforce. Contract law is generally governed by the common law of the State and, while general contract law is common throughout the country, some specific judicial interpretations of a particular element of the treaty may vary between States. However, if your friend gives you a deposit and agrees to pay you $50 per night to stay at home, it`s a contract because you agreed to exchange a service (use of your home) in return ($50 per night). Your friends would have reason to complain if you accepted their payment, but didn`t let them stay at home. A judge may order you to let them stay in your home, or more likely to pay them reasonable expenses related to their stay at the hotel.
If the contract contains uncertain or incomplete clauses and all options for resolving its true meaning have failed, it may be possible to separate and invalidate the relevant clauses only if the contract contains a salvatorial clause. . . .