  Recent observations suggest that a large fraction of Kepler super-Earth
systems have external giant planet companions (cold Jupiters), which can shape
the architecture of the inner planets, in particular their mutual inclinations.
The dynamical perturbation from cold Jupiters may account for the population of
misaligned planets in the Kepler data. The effectiveness of this mechanism can
be hindered by a strong planet--planet coupling in the inner system. In this
paper, we study how mean-motion resonances (MMRs) affect this coupling and the
expected misalignment. We derive approximate analytical expressions for the
mutual inclination excitations in the inner planet system induced by an
inclined companion, for various period ratios and perturber properties. In most
cases, the mutual inclination is proportional to a dimensionless parameter that
characterizes the strength of the perturber relative to the coupling in the
inner system. We show that the MMR strengthens the inner coupling, reducing the
mutual inclination induced by the perturber by a factor of a few. We find that
the resonance is resilient to the perturbation, and derive a criterion for the
libration of the resonant angle. Our results have applications for constraining
unseen planetary perturbers, and for understanding the architecture of
multiplanet systems.
