In the case of Incres Steamship Co., Ltd. v. International Maritime Workers Union et al., 1962, the U.S Supreme Court ruled in favor of Incres Steamship Company, stating that labor disputes involving foreign-flag ships with predominantly foreign crews were not within the jurisdiction of American courts unless there was a clear and substantial impact on American commerce. The dispute began when an Italian ship owned by Incres was picketed by an American union demanding better wages and working conditions for its crew members who were mostly Italian citizens. The court held that applying U.S labor laws to such situations would interfere with international maritime operations and could potentially violate principles of international law.

In the dissenting opinion for the case of Incres Steamship Co., Ltd. v. International Maritime Workers Union et al., Justice Douglas argued that American labor laws should apply to foreign-flag ships when they are in U.S waters, especially if those ships have a significant connection with the United States. He believed that it was not enough to simply consider where a ship is registered or flagged; instead, one must also take into account factors such as ownership and control of operations. In this particular case, he pointed out that although the vessel flew under a Liberian flag, it was owned by an American corporation and operated primarily between New York and Nassau – thus having substantial links with America. Therefore, according to him, U.S labor laws should be applicable on board this ship while in U.S waters so as to protect maritime workers' rights effectively.