  We describe an independent method for determining the strong-isospin breaking
mass parameter, 2delta = m_d - m_u, which utilizes the baryon spectrum. We use
a prudent partially quenched choice of splitting the valence quark masses
symmetrically about the light sea quark mass. This choice has the consequence
of mitigating the most severe partial quenching artifacts. We also discuss the
most significant hurdle to this method which is determining the electromagnetic
self-energy of the neutron-proton mass splitting, a challenge which lacks a
satisfactory answer. Despite these issues, the phenomenologically interesting
dependence of m_n - m_p on delta can be determined.
