Section 27 of the Federal Securities Exchange Act (15 USC 78aa(a)) provides that federal courts have exclusive jurisdiction over suits brought to enforce any liability or duty created by the Exchange Act or any rules or regulations adopted under it.  This decision holds the statute should be interpreted like 28 USC 1331 to confer jurisdiction on federal courts if either (a) the claim is created by the Exchange Act, or rules or regulations adopted under it, or (b) if the suit necessarily raises a stated federal securities law issue, actually disputed and substantial, which a federal forum may maintain without disturbing any congressionally approved balance of state and federal power.