1. these areas: fall into essentially two categories: those in which a federal rule of decision is "necessary to protect uniquely federal interests" and those in which Congress has given the courts the power to develop substantive law. The vesting of jurisdiction in the federal courts does not in and of itself give rise to authority to formulate federal common law, nor does the existence of congressional authority under Art. I mean that federal courts are free to develop a common law to govern those areas until Congress acts. Rather, absent some congressional authorization to formulate substantive rules of decision, federal common law exists only in such narrow areas as those concerned with the rights and obligations of the United States;352 But it is also well established that there is federal common law in a "few and restricted" 353 specific areas. 354 As the Supreme Court explained in Texas Industries