Voting Records of U.S. Senators
Politics that Work rates votes on a wide variety of topics, including economic, social, environmental, labor, civil rights, and fiscal policy in order to provide a standardized means of assessing the voting records of each legislator. Each legislator is scored on a scale for each policy area based on their votes. You can see the full methodology here. The list above contains all of the current Senators. Former legislators are listed here.