“ Today we have again stressed the rule that federal intervention affecting pending state criminal prosecutions, either by injunction or by declaratory judgment, is proper only where irreparable injury is threatened. ”

“ Our sole concern is the determination of whether the statute is constitutionally defective on its face.' The three-judge court then turned to the statute itself, and held that §§ 1 and 2 were unconstitutional, and that § 3 would be constitutional only if the definition of obscenity were changed somewhat. The court issued appropriate declaratory and injunctive relief effectuating its conclusions. ”