關於愛，我是個小學生。

Conflict of laws (or private international law) is a set of procedural rules that determines which legal system and which jurisdiction apply to a given dispute. The rules typically apply when a legal dispute has a "foreign" element such as a contract agreed to by parties located in different countries, although the "foreign" element also exists in multi-jurisdictional countries such as the United Kingdom, the United States, Australia and Canada.
The term conflict of laws itself originates from situations where the ultimate outcome of a legal dispute depended upon which law applied, and the common law courts manner of resolving the conflict between those laws. In civil law, lawyers and legal scholars refer to conflict of laws as private international law. Private international law has no real connection with public international law, and is instead a feature of local law which varies from country to country.
The three branches of conflict of laws are:
Jurisdiction – whether the forum court has the power to resolve the dispute at hand
Choice of law – the law which is being applied to resolve the dispute
Foreign judgments – the ability to recognize and enforce a judgment from an external forum within the jurisdiction of the adjudicating forum.
Terminology
Its three different names – conflict of laws, private international law, and international private law – are generally interchangeable, although none of them is wholly accurate or properly descriptive. The term conflict of laws is primarily used in jurisdictions of the Common Law legal tradition, such as in the United States, England, Canada, and Australia. Private international law (droit international privé) is used in France, as well as in Italy, Greece, and the Spanish- and Portuguese-speaking countries. International private law (internationales Privatrecht) is used in Germany (as well as Austria, Liechtenstein and Switzerland), Russia and Scotland.
Within the federal systems where legal conflicts among federal states require resolution, as in the United States and Australia, the term conflict of laws is preferred simply because such cases do not involve an international issue. Hence, conflict of laws is a general term to refer to disparities among laws, regardless of whether the relevant legal systems are international or inter-state. The term, however, can be misleading when it refers to resolution of conflicts between competing systems rather than "conflict" itself. The term private international law was coined by American lawyer and judge Joseph Story, but was abandoned subsequently by common law scholars and embraced by civil law lawyers.
The stages in a conflict case
The court must first decide whether it has jurisdiction and, if so, whether it is the appropriate venue given the problem of forum shopping.
The next step is the characterisation of the cause of action into its component legal categories which may sometimes involve an incidental question (also note the distinction between procedural and substantive laws).
Each legal category has one or more choice of law rules to determine which of the competing laws should be applied to each issue. A key element in this may be the rules on renvoi.
Once the applicable law is decided, that law must be proved before the forum court and applied to reach a judgment.
The successful party must then enforce the judgment which will first involve the task of securing cross-border recognition of the judgment.
In those states with an underdeveloped set of Conflict rules, decisions on jurisdiction tend to be made on an ad hoc basis, with such choice of law rules as have been developed embedded into each subject area of private law and tending to favour the application of the lex fori or local law. In states with a more mature system, the set of Conflict rules stands apart from the local private civil law and adopts a more international point of view both in its terminology and concepts. For example, in the European Union, all major jurisdictional matters are regulated under the Brussels Regime, e.g. the rule of lis alibi pendens from Brussels 1 Regulation applies in the Member States and its interpretation is controlled by the European Court of Justice rather than by local courts. That and other elements of the Conflict rules are produced supranationally and implemented by treaty or convention. Because these rules are directly connected with aspects of sovereignty and the extraterritorial application of laws in the courts of the signatory states, they take on a flavour of public rather than private law because each state is compromising the usual expectations of their own citizens that they will have access to their local courts, and that local laws will apply in those local courts. Such aspects of public policy have direct constitutional significance whether applied in the European context or in federated nations such as the United States, Canada, and Australia where the courts have to contend not only with jurisdiction and law conflicts between the constituent states or territories, but also as between state and federal courts, and as between constituent states and relevant laws from other states outside the federation.
Choice of law rules
Courts faced with a choice of law issue have a two-stage process:
the court will apply the law of the forum (lex fori) to all procedural matters (including, self-evidently, the choice of law rules); and
it counts the factors that connect or link the legal issues to the laws of potentially relevant states and applies the laws that have the greatest connection, e.g. the law of nationality (lex patriae) or domicile (lex domicilii) will define legal status and capacity, the law of the state in which land is situated (lex situs) will be applied to determine all questions of title, the law of the place where a transaction physically takes place or of the occurrence that gave rise to the litigation (lex loci actus) will often be the controlling law selected when the matter is substantive, but the proper law has become a more common choice.
Conflict of law rules in matrimonial cases:
Marriage (conflict)
In divorce cases, when a court is attempting to distribute marital property, if the divorcing couple is local and the property is local, then the court applies its domestic law lex fori. This becomes much more complicated when local laws allow polygamy. For example, Saskatchewan Canada stands alone as a province in Canada that allows more than one spouse at a time per person. Each province has similar marital property laws, but what happens when one or more provinces ignore the federal polygamy law? In this case some of the spouses receive/give marital property from two or more simultaneous spouses, while others may only receive/give from one spouse only, depending on whether their home province allows polygamy. The case becomes even more complicated if foreign elements are thrown into the mix, such as when the place of marriage is different from the territory where divorce was filed; when the parties' nationalities and residences do not match; when there is property in a foreign jurisdiction; or when the parties have changed residence several times during the marriage. Each time a spouse invokes the application of foreign law, the process of divorce slows down, as the parties are directed to brief the issue of conflict of laws and provide translations of the foreign laws.
Different jurisdictions follow different sets of rules. Before embarking on a conflict of law analysis, the court must determine whether a property agreement governs the relationship between the parties. The property agreement must satisfy all formalities required in the country where enforcement is sought.
Whereas commercial agreements or prenuptial agreements generally do not require legal formalities to be observed, when married couples enter a property agreement, stringent requirements are imposed, including notarization, witnesses, special acknowledgment forms. In some countries, these must be filed (or docketed) with a domestic court, and the terms must be "so ordered" by a judge. This is done in order to ensure that no undue influence or oppression has been exerted by one spouse against the other. Upon presenting a property agreement between spouses to a court of divorce, that court will generally assure itself of the following factors: signatures, legal formalities, intent, later intent, free will, lack of oppression, reasonableness and fairness, consideration, performance, reliance, later repudiation in writing or by conduct, and whichever other concepts of contractual bargaining apply in the context.
In the absence of a valid and enforceable agreement, here's how the conflict of law rules work:
Movable v. Real Estate
In general, applicable matrimonial law depends on the nature of the property. Lex situs is applied to immovable property (i.e., real estate), and the law of matrimonial domicile applies to movable property, provided there has been no subsequent change in the spouses' domicile.
Full Mutability Doctrine 
Property relations between spouses are governed by their latest domicile, whether acquired before or after the marriage. This is also the norm in England, except for a few cases where severe injustice results from a harsh application. In those cases, the court also examines whether newly acquired property can be traced back to property owned before the change.
Immutability Doctrine 
The original personal law of the parties at the time of marriage continues to govern all property including subsequently acquired property, regardless of a later change in domicile or nationality. This is the Continental approach in France, Germany and Belgium. Also, with certain reservations, see Art. 7 of the 1976 Hague Convention on Marriage and Matrimonial Property Regimes. Also in Israel: "Property relations between spouses shall be governed by the law of their domicile at the time of the solemnization of the marriage, provided that they may by agreement determine and vary such relations in accordance with the law of their domicile at the time of making the agreement". Note that the Israeli application of the Immutability Doctrine does not distinguish between personal and real property. Both are subject to the law of domicile at marriage.
Partial Mutability or Mutability of New Acquisition
This is the American approach to conflicts of law in matrimonial property division cases. All movable property acquired during the marriage is subject to the parties' domicile law at the time of acquisition, and not that of the original or intermediate domicile. What was acquired before the marriage is governed by the law of the parties' domicile at the time of marriage. Thus, if rights vested in a property when and where it was purchased, it would not be adversely affected by a later change of domicile.
Lex Fori - In many cases, courts simply avoid this complicated and expensive analysis by applying their local law to the parties' entire property, even if there is a foreign element. This is based on the assumption that laws around the world are basically similar in their treatment of marriage as a co-partnership. Since the partnership can be placed in the forum, the forum's law applies to all its aspects.
Note that Lex Fori also applies to all procedural relief (as opposed to substantive relief). Thus, issues such as the ability to grant pre-trial relief, procedure and form, as well as statutes of limitations are classified as "procedure" and are always subject to domestic law where the divorce case is pending.
Conflict of law rules in unmarried cases
Unlike marriage which has an international recognised legal status, there are no international treaties on recognition of unmarried couple's legal status. If an unmarried couple change residence to different countries, then the local law on where the couple is last domiciled is applied to them. This covers, legal; status of the relationship, rights, obligations and all worldwide movable and immovable property. To otherwise interpret the law would mean if the unmarried couple had assets in several different countries, they would then need separate legal cases in each country to resolve all their movable and immovable property.
In the absence of a valid and enforceable agreement for an unmarried couple, here’s how the conflict of law rules work:
Full Mutability Doctrine - property relations between the unmarried couples are governed by their latest domicile, whether acquired before, during or after the relationship.
Pre-dispute provisions
Many contracts and other forms of legally binding agreement include a jurisdiction or arbitration clause specifying the parties' choice of venue for any litigation (called a forum selection clause). Then, choice of law clauses may specify which laws the court or tribunal should apply to each aspect of the dispute. This matches the substantive policy of freedom of contract. Judges have accepted that the principle of party autonomy allows the parties to select the law most appropriate to their transaction. Obviously, this judicial acceptance of subjective intent excludes the traditional reliance on objective connecting factors, but it does work well in practice.
The status of foreign law
Generally, when the court is to apply a foreign law, it must be proved by foreign law experts. It cannot merely be pleaded, as the court has no expertise in the laws of foreign countries nor in how they might be applied in a foreign court. Such foreign law may be considered no more than evidence, rather than law because of the issue of sovereignty. If the local court is actually giving extraterritorial effect to a foreign law, it is less than sovereign and so acting in a way that is potentially unconstitutional. The theoretical responses to this issue are:
(a) that each court has an inherent jurisdiction to apply the laws of another country where it is necessary to achieving a just outcome; or
(b) that the local court creates a right in its own laws to match that available under the foreign law. This explanation is sustainable because, even in states which apply a system of binding legal precedents, any precedent emerging from a conflicts case can only apply to future conflicts cases. There will be no ratio decidendi that binds future litigants in entirely local cases.
(c) that the national court, when applying a foreign law, does not give an extraterritorial effect but recognizes, through its own "conflict of laws rule", that the situation at hand falls under the scope of application of the foreign rule. In order to understand this argument one must first define the notion of extraterritorial application of a rule. This notion is susceptible to two distinct meanings:
On the one hand, this notion is used to describe the situation where a local court applies a rule other than the Lex fori (local law).
On the other hand, it could mean that the rule is being applied to a factual situation that occurred beyond the territory of its state of origin. As an example of this situation, one can think of an American court applying British tort statutes and case law to a car accident that took place in London where both the driver and the victim are British citizens but the lawsuit was brought in before the American courts because the driver's insurer is American. One can then argue that since the factual situation is within the British territory, where an American judge applies the English Law, he does not give an extraterritorial application to the foreign rule. In fact, one can also argue that the American judge, had he applied American Law, would be doing so in an extraterritorial fashion.
Once the lex causae has been selected, it will be respected except when it appears to contravene an overriding mandatory rule of the lex fori. Each judge is the guardian of his own principles of ordre public (public order) and the parties cannot, by their own act, oust the fundamental principles of the local municipal law which generally underpin areas such as labour law, insurance, competition regulation, agency rules, embargoes, import-export regulations, and securities exchange regulations. Furthermore, the lex fori will prevail in cases where an application of the lex causae would otherwise result in a fundamentally immoral outcome, or give extraterritorial effect to confiscatory or other territorially limited laws.
In some countries, there is occasional evidence of parochialism when courts have determined that if the foreign law cannot be proved to a "satisfactory standard", then local law may be applied. In the United Kingdom, in the absence of evidence being led, the foreign law is presumed to be the same as the lex fori. Similarly, judges might assume in default of express evidence to the contrary that the place where the cause of action arose would provide certain basic protections, e.g. that the foreign court would provide a remedy to someone who was injured due to the negligence of another. Finally, some American courts have held that local law will be applied if the injury occurred in an "uncivilized place that has no law or legal system."
If the case has been submitted to arbitration rather than a national court, say because of a forum selection clause, an arbitrator may decide not to apply local mandatory policies in the face of a choice of law by the parties if this would defeat their commercial objectives. However, the arbitral award may be challenged in the country where it was made or where enforcement is sought by one of the parties on the ground that the relevant ordre public should have been applied. If the lex loci arbitri has been ignored, but there was no real and substantial connection between the place of arbitration and the agreement made by the parties, a court in which enforcement is sought may well accept the tribunal's decision. But if the appeal is to the courts in the state where the arbitration was held, the judge cannot ignore the mandatory provisions of the lex fori.
Harmonization
To apply one national legal system as against another may never be an entirely satisfactory approach. The parties' interests may always be better protected by applying a law conceived with international realities in mind. The Hague Conference on Private International Law is a treaty organization that oversees conventions designed to develop a uniform system. The deliberations of the conference have recently been the subject of controversy over the extent of cross-border jurisdiction on electronic commerce and defamation issues. There is a general recognition that there is a need for an international law of contracts: for example, many nations have ratified the Vienna Convention on the International Sale of Goods, the Rome Convention on the Law Applicable to Contractual Obligations offers less specialized uniformity, and there is support for the UNIDROIT Principles of International Commercial Contracts, a private restatement, all of which represent continuing efforts to produce international standards as the internet and other technologies encourage ever more interstate commerce. But other branches of the law are less well served and the dominant trend remains the role of the forum law rather than a supranational system for Conflict purposes. Even the EU, which has institutions capable of creating uniform rules with direct effect, has failed to produce a universal system for the common market. Nevertheless, the Treaty of Amsterdam does confer authority on the Community's institutions to legislate by Council Regulation in this area with supranational effect. Article 177 would give the Court of Justice jurisdiction to interpret and apply their principles so, if the political will arises, uniformity may gradually emerge in letter. Whether the domestic courts of the Member States would be consistent in applying those letters is speculative.

待續