Evasion in law, is a fundamental public policy doctrine, which exists also in the conflict of laws. Definition Although one may legitimately plan affairs to avoid the incidence of obligations or liabilities imposed by the law, but no one may evade the operation of otherwise-mandatory provisions if duties and liabilities have been properly imposed or incurred. It is a standard doctrine in most jurisdictions: in France, it is termed, fraude à la loi, in Spain, fraude de ley, in Italy, frode alla legge, in Germany, Gesetzesumgehung. It reflects the need for governments to prevent their citizens from intentionally and improperly manipulating their behaviour to prevent mandatory provisions in the law from applying to them. As the translated names necessarily imply, the key is an intention to displace the normal operation of the legal system. Sometimes, that intention is obvious. On other occasions, it is for the courts to decide whether a sufficient intention can be imputed. Once the intention is established, the evasive manoeuvre is void, and the normal legal provisions will apply to the parties. Taxation Almost all states operate a collection system for taxation revenues within a framework of law that is enforced by independent courts. Enabling statutes must be strictly applied, and it is generally against public policy to allow the tax administration to agree to reduce the amount of tax payable by any individual. Like criminal law in which agreements by the policing authorities to exempt a criminal are prohibited, tax law has a special status as being essential to an organised society in maintaining public trust through the policy of equal treatment in the legal system. Nevertheless, a taxpayer who organises affairs to exploit a loophole in the law to avoid the incidence of tax liability will usually be permitted to do so. It is not for the courts to legislate and plug the gaps left by the legislature. The test of avoidance is whether there is a legitimate purpose for the given behaviour. Many states adopt a "business purpose" test, by decomposing the transaction into its component steps to determine the true purpose of the transaction(s) (see tax avoidance). Family law In Family law, the citizens of any state may not be allowed to evade rules like those on marriage by blood relatives or by persons of the same biological sex only by travelling to and going through a ceremony in a state that