The location of the parties or their assets does not necessarily decide which jurisdiction controls -- but that determination can prove critical to the outcome. Asset-disclosure laws in Japan, for example, are relatively lax compared with those in the United States. Prenuptial agreements are more frequently enforced here than in England. Cheating spouses in France often pay more in support than they would elsewhere. Alimony laws vary greatly.
"Both parties are after the laws to their advantage," said Katharine Maddox, a family lawyer in Tysons Corner, Va., and fellow of the International Academy of Matrimonial Lawyers. Understanding the differing laws is complicated enough, but managing cultural nuances at the same time is tricky, too. For example, dowries are illegal in India but common nonetheless, she said. Maddox has had cases in which a divorcing woman wanted to get her dowry back once the couple split -- an impossibility under the law.
In another case, a client from Egypt sought Maddox's advice about arranging for her divorcing husband to buy a home for her and their children. In Egypt, the husband frequently must provide such accommodations upon divorce. Not so, here. "She believed she had a right to that," Maddox said.
Maddox, who, like other international divorce attorneys spends a good deal of time traveling abroad on client matters, also networks often with members of the International Academy of Matrimonial Lawyers, which helps bring in business and provides a roster of attorneys all over the world to whom she can refer cases.
Obviously, the most effective attorneys understand the laws and customs of the countries involved, said Garrison, the law professor. But getting one's hands on the appropriate statutes and treatises can be a huge challenge. Lawyers here are accustomed to clicking on Lexis or Westlaw; browsing the family law statutes in Estonia, for example, is much tougher, she said.
"There is an enormous amount of difficulty even in giving your client advice on which jurisdiction to file in," Garrison said.
The most complicated cases involve custody and child support, said Jeremy Morley, an international divorce solo practitioner in New York. "Money is just numbers in the bank. Children are different," he said. Morley charges about $500 an hour, he said.
Most countries continue to favor the mother in custody battles, but in Muslim countries, for instance, the father often is declared the custodial parent of children who have reached school age.
In bitter international custody battles, sometimes one parent fears the other will take the children abroad, Morley said. There is reason for that concern: In 2010, nearly 1,500 children were abducted by family members from the United States, according to the U.S. Department of State.
Maddox just took on as a client a Mexican citizen whose wife refused to return to Virginia with the children following a family visit to Mexico City. She is petitioning the Virginia court to order the kids returned. "Once we have court orders for custody, we will initiate an international Hague petition," she said.