WordNet (r) 3.0 (2006):

party line
    n 1: the policy of a political group; "He won in a vote along
         party lines"
    2: a telephone line serving two or more subscribers

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "party line":
   WATS, WATS line, autarky, bimetallism, cable, co-ax, coaxial cable,
   concentric cable, economic self-sufficiency, free enterprise,
   free trade, governmentalism, laissez-faire, laissez-faireism, line,
   localism, managed currency, noninterference, nonintervention,
   nullification, party principle, planned economy, policy, polity,
   position, price supports, private line, protection, protectionism,
   public policy, pump-priming, sectionalism, telegraph cable,
   telegraph line, telephone line, trunk, trunk line, wire line