Mayer Brown cover a ruling on a case we've talked about before. I won’t go into detail on the case, as I have posted lots on Section 1782 before, but the Court’s holding is interesting.
In an unanimous holding, the US Supreme Court found that 28 U.S.C. §1782 does not apply to either private commercial arbitration or to ad hoc investor-state arbitration under a bilateral investment treaty. This decision is important as it removes a much favoured and useful tool for parties to international arbitration seeking to obtain discovery from US entities in support of arbitrations.
The position in the United States now stands in contrast to the position in England. In A v C  1 WLR 3504, the (English) Court of Appeal held that parties to a foreign seated arbitration may use section 44 of the Arbitration Act 1996 to obtain an order from the English courts for the taking of evidence of witnesses in support of that foreign arbitration.
For previous piece on Section 1782 please see below:
Section 1782 authorizes federal district courts to order the production of documents to be used in foreign or international proceedings only if the proceeding occurs before “a foreign or international tribunal.” 28 U.S.C. § 1782(a).