A federal judge on Tuesday declined to dissolve a consent decree that has set limits on polling activities around the country for nearly 30 years but he did make some modifications.

The ruling, in Democratic National Committee v. Republican National Committee, 81-Civ.-3876, redefines or clarifies the “ballot security” and poll-watching activities subject to the decree, restricts who can enforce it, and for the first time, sets an end date — eight years from now.