In January 2002, Republican President George W. Bush signed into law the No Child Left Behind (NCLB) Act, the reauthorized Elementary and Secondary Education Act (ESEA) of 1965. The most conservative congressional Republicans, who opposed the bill's extensive new testing mandates and absence of school voucher provisions, were largely left out in the cold as the president won a major domestic political victory. In fact, House Education and Workforce Committee chairman John Boehner (R-OH), one of Gingrich's ardent supporters, threw his support behind Bush's bill. This chapter attempts to answer questions about the politics of the adoption of this law in the 106th and 107th Congresses over the 3-year period 1999-2002 and the dramatic shifts in both political parties' positions on federal education policy. Also considered are the implications of these party realignments for education policy in the 109th Congress. The events that took place over the course of the two Congresses--gridlock in one and the passage of legislation in the other--highlight different aspects of the political environment during this period. They also reveal how political coalitions came apart, new ones formed, and partisan gridlock was overcome. Throughout this chapter, the themes of partisanship and ideology are traced, specifically their varying effects on congressional behavior at different stages of the legislative process. The education policy background during the 1990s, both the Clinton legacy and the conservative opposition to the standards movement preceding the 1998-1999 reauthorization process, is reviewed. Subsequently, the major developments in the 106th and 107th Congresses that led to the passage of NCLB are outlined. The author then focuses on one of the themes that was common across the two Congresses: the shifting dynamic among education interest groups, congressional staffs, and the executive branch. Finally, she discusses the implications of the party realignments in terms of education policy for the Bush second term and the 109th Congress. [This article represents Chapter 2 of "The Elementary and Secondary Education Act at 40: Reviews of Research, Policy Implementation, Critical Perspectives, and Reflections," "Review of Research in Education," v29, 2005 (EJ748131).]