(a) Notwithstanding any final judgment rendered in any action brought by the United States under which a joint operating arrangement has been held to be unlawful under any antitrust law, any party to such final judgment may reinstitute said joint newspaper operating arrangement to the extent permissible under section 1803 (a) of this title.

(b) The provisions of section 1803 of this title shall apply to the determination of any civil or criminal action pending in any district court of the United State [1] on July 24, 1970, in which it is alleged that any such joint operating agreement is unlawful under any antitrust law.