A current debate in congressional behavior research surrounds the continued adherence to norms of legislative behavior, especially “legislator expertise” or specialization. We examine the degree to which senators adhere to the traditional specialization norm of the U.S. Senate. Based on an analysis of primary sponsorship in the 101st Congress, this study finds that the specialization norm is still present in the contemporary Senate, but that type of specialization is an important distinction to make when evaluating the strength of the norm. We identify two forms of specialization: institutional and personal. Using this construct, we find that legislators who deemphasize institutional specialization are often electorally vulnerable and/or facing reelection soon. These senators placed less emphasis on focused legislative activity, presumably to engage in constituency‐oriented sponsorship of legisl