  The nonconcensus opinion model (NCO) introduced recently by Shao et al.,
[Phys. Rev. Lett.103, 018701 (2009)] is solved exactly on the line. Although,
as expected, the model exhibits no phase transition in one dimension, its study
is interesting because of the connection with invasion percolation with
trapping. The system evolves exponentially fast to the steady-state, rapidly
developing long-range correlations: The average cluster size in the steady
state scales as the square of the initial cluster size, of the (uncorrelated)
initial state. We also discuss briefly the NCO model on Bethe lattices, arguing
that its phase transition diagram is different than that of regular
percolation.
