  Recent advances in sub-millimeter observations of young circumstellar nebulae
have opened an unprecedented window into the structure of protoplanetary disks,
which has revealed the surprising ubiquity of broken and misaligned disks. In
this work, we demonstrate that such disks are capable of torquing the spin axis
of their host star, representing a hitherto unexplored pathway by which stellar
obliquities may be generated. The basis of this mechanism is a crossing of the
stellar spin precession and inner disk regression frequencies, resulting in
adiabatic excitation of the stellar obliquity. We derive analytical expressions
for the characteristic frequencies of the inner disk and star as a function of
the disk gap boundaries, and place an approximate limit on the disk
architectures for which frequency crossing and resulting obliquity excitation
are expected, thereby illustrating the efficacy of this model. Cumulatively,
our results support the emerging concensus that significant spin-orbit
misalignments are an expected outcome of planet formation.
