The Obama administration realized that it must also contend with the findings of numerous US government and news reports that the US nuclear complex (the national laboratories and production and other facilities), and its aging nuclear weapon arsenal required modernization. The connection between the follow-on treaty and the Nuclear Posture Review became increasingly important in terms of domestic politics, particularly among Republican senators such as Senator Jon Kyl of Arizona, considered to be the Republican expert on nuclear strategy and weapons. The Nuclear Posture Review surfaced as a more prominent topic because it was required to address the modernization issue.