roadblock
 n.— «The great advantage Reagan enjoys is the three-network whammy, what Matthews calls a “roadblock.” When Reagan speaks on all three networks at once, he is making it very difficult for viewers to avoid him, but the Democrats rarely enjoy this advantage when they finally get air time to make their responses.» —“Panning The Reagan Show TV Privileges Abroad, House Democrats Charge On the Air” by Tom Shales Washington Post Oct. 3, 1984. (source: Double-Tongued Dictionary)