Black's Law Dictionary, 6th Ed.
Conflict of laws. Inconsistency or difference between the laws of different states or countries, arising in the case of persons who have acquired rights, incurred obligations, injuries or damages, or made contracts, within the territory of two or more jurisdictions. Hence, that branch of jurisprudence, arising from the diversity of the laws of different nations, states or jurisdictions, in their application to rights and remedies, which reconciles the inconsistency, or decides which law or system is to govern in the particular case, or settles the degree of force to be accorded to the law of another jurisdiction, (the acts or rights in question having arisen under it) either where it varies from the domestic law, or where the domestic law is silent or not exclusively applicable to the case in point. Restatement, Second, Conflicts of Law, Sec. 2. See also Center of gravity doctrine; Choice of law; Grouping of contacts; Kilberg doctrine; Lex celebrationis; Lex loci contractus; Lex situs; Lex solutionis; Lex validitatis; Renvoi doctrine.
Bouvier's Law Dictionary
CONFLICT OF LAWS. This phrase is used to signify that the laws of different countries, on the subject−matter to be decided, are in opposition to each other; or that certain laws of the same country are contradictory.
2. When this happens to be the case, it becomes necessary to decide which law is to be obeyed. This subject has occupied the attention and talents of some of the most learned jurists, and their labors are comprised in many volumes. A few general rules have been adopted on this subject, which will here be noticed.
3. − 1. Every nation possesses an exclusive sovereignty and jurisdiction within its own territory. The laws of every state, therefore, affect and bind directly all property, whether real or personal, within its territory; and all persons who are resident within it, whether citizens or aliens, natives or foreigners; and also all contracts made, and acts done within it. Vide Lex Loci contractus; Henry, For. Law, part 1, c. 1, 1; Cowp. It. 208; 2 Hag. C. R. 383. It is proper, however, to observe, that ambassadors and other public ministers, while in the territory of the state to, which they are delegates, are exempt from the local jurisdiction. Vide Ambassador. And the persons composing a foreign army, or fleet, marching through, or stationed in the territory of another state, with whom the foreign nation is in amity, are also exempt from the civil and criminal jurisdiction of the place. Wheat. Intern. Law, part 2, c. 2, _10; Casaregis, Disc. 136−174 vide 7 Cranch, R. 116.
4. Possessing exclusive authority, with the above qualification, a state may regulate the manner and circumstances, under which property, whether real or personal, in possession or in action, within it shall be held, transmitted or transferred, by sale, barter, or bequest, or recovered or enforced; the condition, capacity, and state of all persons within it the validity of contracts and other acts done there; the resulting rights and duties growing out of these contracts and acts; and the remedies and modes of administering justice in all cases. Story, Confl. of Laws, _18; Vattel, B. 2, c. 7, _84, 85; Wheat. Intern. Law, part 1, c. 2, _5.
5. − 2. A state or nation cannot, by its laws, directly affect or bind property out of its own territory, or persons not resident therein, whether they are natural born or naturalized citizens or subjects, or others. This result flows from the principle that each sovereignty is perfectly independent. 13 Mass. R. 4. To this general rule there appears to be an exception, which is this, that a nation has a right to bind its own citizens or subjects by its own laws in every place; but this exception is not to be adopted without some qualification. Story, Confl. of Laws, _21; Wheat.
Intern. Law, part 2, c. 2, _7.
6. − 3. Whatever force and obligation the laws of one, country have in another, depends upon the laws and municipal regulations of the latter; that is to say, upon its own proper jurisprudence and polity, and upon its own express or tacit consent. Huberus, lib. 1, t. 3, _2. When a statute, or the unwritten or common law of the country forbids the recognition of the foreign law, the latter is of no force whatever. When both are silent, then the question arises, which of the conflicting laws is to have effect. Whether the one or the other shall be the rule of decision must necessarily depend on a variety of circumstances, which cannot be reduced to any certain rule. No nation will suffer the laws of another to interfere with her own, to the injury of her own citizens; and whether they do or not, must depend on the condition of the country in which the law is sought to be enforced, the particular state of her legislation, her policy, and the character of her institutions. 2 Mart. Lo. Rep. N. S. 606. In the conflict of laws, it must often be a matter of doubt which should prevail; and, whenever a doubt does exist, the court which decides, will prefer the law of its own country to that of the stranger. 17 Mart. Lo. R. 569, 595, 596. Vide, generally, Story, Confl. of Laws; Burge, Confl. of Laws; Liverm. on Contr. of Laws; Foelix, Droit Intern.; Huberus, De Conflictu Leguin; Hertius, de Collisions Legum; Boullenois, Traits de Ia personnalite’ et de la realite de lois, coutumes et statuts, par forme d’observations; Boullenois, Dissertations sur des questions qui naissent de la contrariete des lois, et des coutumes.