  We present a "Chern-Simons-like" action for the "general massive gravity"
model propagating two spin-2 modes with independent masses in three spacetime
dimensions (3D), and we use it to find a simple Hamiltonian form of this model.
The number of local degrees of freedom, determined by the dimension of the
physical phase space, agrees with a linearized analysis except in some limits,
in particular that yielding "new topologically massive gravity", which
therefore suffers from a linearization instability.
