I have less to say about federal-question jurisdiction, because the ALI has done much better with this subject than with diversity. The jurisdiction itself, unlike diversity, is not very controversial, despite the well-known fact that it did not exist in the trial courts until 1875; 224 it seems dear that if we are to have original federal jurisdiction at all it ought to extend to the enforcement of federal rights. The Institute accurately marshals the arguments: Federal judges have relative expertise in dealing with federal law; uniform interpretation is promoted by federal jurisdiction; state courts may be hostile to federal law. Supreme Court review of state courts, limited by narrow review of the facts, the debilitating possibilities of delay, and the necessity of deferring to adequate state grounds of decision, cannot do the whole job. The Institute endorses the general federal-question jurisdiction of the district courts in order" to protect litigants relying on federal law from the danger that state courts will not properly apply that law, either through misunderstanding or lack of sympathy.'225 I agree, and I shall not expand on the argument for the jurisdiction. One difficulty with federal-question jurisdiction is that nobody knows how to define it. Its constitutional scope is quite broad. Despite smoke screens thrown up by dissenting opinions, 22 however, the Supreme Court has never suggested the jurisdiction includes the vast category of cases in which there are potential federal issues. The test of the famous Osborni case is rather that the case must contain some" ingre-t Professor of Law, The University of Chicago. This is the second installment of a two-part article. The first part appeared in the Fall i968 Issue, 36 U. CHI. L. kEV. 1-49.