Online voter registration (OVR) is an election reform that has recently taken hold in more than half of the American states. Election administration observers have marveled at both the rapid diffusion and bipartisan support associated with legislative passage of OVR. We examine the likelihood a lawmaker voted in favor or against OVR in legislatures approving the reform. Despite the leading narrative of both parties overwhelmingly embracing OVR, we find that lawmaker support is clearly rooted in political calculations. Most prominent is a partisan divide, with Republicans in polarized legislatures with a Democratic majority decidedly less supportive of OVR. In addition, a host of contextual factors tied to the variation in partisan and electoral power affect the probability a state legislator votes in favor of this reform. We argue that the near-consensus position of Democrats (more than 90% voted "yea" on OVR) and the impressive supermajority of Republicans backing OVR (greater than 70%) have diverted attention from the reasons why there is opposition to this seemingly noncontroversial reform.