European readers, who love to hate US pretrial discovery—this one is for you. Absent action by Congress, on December 1, 2015, an amendment to FRCP 26 adopted by the Supreme Court will go into effect. The main change concerns the scope of permissible pretrial discovery. Under the old rule:

Parties may obtain discovery regarding any nonprivileged matter that is relevant to any party’s claim or defense.

But under the new rule:

Parties may obtain discovery regarding any nonprivileged matter that is relevant to any party’s claim or defense and proportional to the needs of the case, considering the importance of the issues at stake in the action, the amount in controversy, the parties’ relative access to relevant information, the parties’ resources, the importance of the discovery in resolving the issues, and whether the burden or expense of the proposed discovery outweighs its likely benefit.

Of course, we don’t know how courts will apply the new rule yet, how they will weigh the factors mentioned in the rule, and so forth. It’s possible that the rule will mark a dramatic change in US practice, and it’s possible that the rule will make hardly any difference at all in practice. If I had to guess, I would guess that it will make a difference at the margins; but courts and parties were already on a road to dealing with the problems of proportionality raised by e-discovery anyway. In principle, though, the amendment to Rule 26 is a major conceptual change in the theory of US pretrial discovery that should be welcome to the many critics of the breadth of US pretrial discovery.