Abstract. One of the large new projects envisioned for the future US nuclear physics program is the construction of a high-energy electron ion collider. The motivation for such a machine would be primary directed at the study of the nucleon spin structure using polarized light ions and the study of low x gluon distributions in heavy nuclei. Two candidates coming from the two large DOE nuclear physics facilities, one at Brookhaven called eRHIC, and one at Jefferson Laboratory called ELIC are the primary candidates today.