This is one of a set of posts serializing my law review article on this subject; please see the article for footnotes  and for more details.] As I noted at the end of the previous post, the benefits of bans on the use of foreign law are likely to be small — but the costs could be grave. Foreign law is routinely used in American courts, but in everyday cases applying existing American legal rules related to family law, contract law, tort law, evidence law and the like. Those American legal rules (such as “choice of law” rules) often expressly call for the consideration of foreign law; here I focus on two more examples, tort law and the reference to marital status in the law of evidence.

Tort law: Let us say a Canadian (Don) injures an Oklahoman (Paul) in Canada, and then Don moves to Oklahoma before a lawsuit is filed, perhaps because he works at Devon Energy Corp. and was transferred to its Oklahoma office. Paul sues Don in Oklahoma, where the plaintiff and defendant both now live and where defendant’s assets are now located. Generally speaking, in such a case Oklahoma courts would apply Canadian law.

For example, let us say the injury happened in an automobile accident, and Paul claims that Don was driving unreasonably. We would naturally want to see if Don was violating traffic laws. Which traffic laws? Canadian traffic laws. We wouldn’t ask if Don was driving in violation of an Oklahoma traffic law while driving in Canada.

The same would be true for other types of tort law, or if an Oklahoman injured a Canadian in Canada, rather than vice-versa. There are complicated choice of law questions as to which laws should apply in certain situations. But in many situations, it’s clear that the proper application of choice of law rules requires foreign law to be applied.

If the option of applying Canadian law were eliminated, Oklahoma courts would have two alternatives. First, they could apply Oklahoma law, even though the accident happened in Canada. For the reasons mentioned above, that would be unwise. It would be unfair to the litigants, who were understandably expecting that they should follow Canadian rules of the road and not Oklahoma rules of the road. And it would likely produce tension with foreign countries, which would be bad for businesses that employ many Americans.

Second, Oklahoma courts could just refuse to decide the case and insist that the case instead be decided by Canadian courts. “We cannot apply Oklahoma law,” these hypothetical courts would say, “because this case involves a Canadian accident. And we cannot apply Canadian law because that would be considering foreign law and that would be bad.”

But is this what Oklahomans really want? Oklahomans should, I think, prefer that they have an opportunity to litigate in their own state, rather than having to travel to another country to sue. So instead of just refusing to decide cases that are based on out-of-state events, or applying Oklahoma law where it would clearly be inapt, Oklahoma courts apply choice of law principles — principles that are not the invention of some liberal law professor but have existed throughout American history.

Evidence law: Or consider situations where various bodies of law, such as evidence law, turn on people’s marital status. For example, suppose Heinz and Wilhelmina are a couple, and Heinz is accused of a crime in Oklahoma. May Wilhelmina be compelled to testify about what Heinz told her? Well, Oklahoma law provides that, if the two are married, then Heinz may prevent Wilhelmina from testifying about any confidential communications that the two shared.

Say, though, that Heinz had been married before, to his ex-wife Erica. So, to figure out if Heinz and Wilhelmina are married, a court must decide whether Heinz and Erica were properly divorced. And say the purported divorce and marriage happened in Austria, and Heinz and Wilhelmina are visiting Oklahoma (whether for business or pleasure).

To determine whether the marriage and the divorce were proper, Oklahoma courts can’t ask whether the couple complied with American marriage law or divorce law. Of course the divorce didn’t comply with American divorce law. Why should it have? It stemmed from an Austrian proceeding, which followed Austrian rules. When Heinz divorced and remarried, he never expected to be in America many years later.

So Oklahoma courts would turn, as in Ghassemi, to the standard rule of family law, which is to determine the validity of a marriage or a divorce by applying the law of the jurisdiction where either took place. There is nothing particularly radical about such rules. But if Oklahoma courts cannot consider foreign law, how can they possibly make these marital status decisions that are needed to apply American law?

Again, it is American law that says a spouse may not testify about confidential communications. And it is American law that says whether a person is married or divorced is to be determined under the law of the jurisdiction where the marriage or divorce took place. But applying this American law requires courts to consider Austrian law.

I hope I’ve shown, then, that American courts should indeed keep using foreign law in those situations in which well-established American law calls for such use. Tomorrow, I want to turn to some specific proposals for restricting the application of foreign law, and why I think they’re mistaken.