Modeling the formation and evolution of galaxies has long been a challenge because of the dual requirements of modeling large and small scales. Recent numerical work has demonstrated that highly effective feedback from star formation (and AGN, although here I will focus mostly on stars), can drive strong outflows and reproduce many of the observed properties of galaxies. However, our understanding of the physical processes behind that feedback is still unsettled. Here I explore the dynamical impact of cosmic rays under the assumption that they are efficiently generated in supernovae explosions and diffuse throughout the galaxy, demonstrating that they can drive substantial outflows. I also examine the impact of cosmic rays on the circumgalactic medium and the structure of dwarf galaxies, showing that these are important additional constraints on feedback properties.