INTRODUCTION

Arthur von Mehren's last and most ambitious project, a Hague Convention unifying rules on international jurisdiction and foreign judgments, did not come to fruition. One reason was prevailing differences over substantive issues – differences that have been discussed at length. Such differences might have been overcome through compromise had there not been a problem that has received less attention but may have been more fundamental, precisely because it was not fully recognized: Most delegates implicitly presumed that judgments conventions must take on a certain shape. One such presumption that has been discussed was that all jurisdictional bases in a convention must be either required (so that courts in all member states must exercise jurisdiction under certain circumstances), or excluded (so that courts are not allowed to exercise jurisdiction under certain circumstances). A second assumption, less well-recognized, was that conventions that regulate jurisdiction, in addition to recognition and enforcement of judgments, must be symmetrical: If a judgment rests on a required basis of jurisdiction, other states must be obliged to enforce it (unless there are other reasons not to enforce it, such as fraud); if it rests on an excluded basis, other states must be restrained from enforcing it.

Both assumptions are wrong, and Arthur von Mehren worked tirelessly to show this. The alternative he developed was the mixed convention, an ingenious model to bridge the gap between single conventions (conventions that regulate only the recognition of foreign judgments) and double conventions (conventions that regulate jurisdiction both at the decision stage and at the recognition stage).