This article studies the consensus problem for continuous-time linear time-invariant multiagent systems, in which the agents exchange information through delayed communication channels in a fixed undirected topology. Our primary objective is to characterize explicitly the delay effect on consensus in the framework of distributed dynamic output feedback control and its implication on the graph network connectivity. For this purpose, we tackle and solve the consensus problem in the spirit of gain margin problem, using analytic interpolation techniques. We develop an explicit condition for consensus. The result provides a limit on network connectivity imposed by time delays as well as by the agent's unstable poles and nonminimum phase zeros.