On December 11, 1972, we noted probable jurisdiction of this appeal, 409 U. S. 1058, based on a jurisdictional statement presenting the single question whether the prohibition in § 9 (a) of the Hatch Act, now codified in 5 U. S. C. § 7324 (a) (2), against federal employees taking "an active part in political management or in political campaigns," is unconstitutional on its face. Section 7324 (a) provides: