This article is a policy analysis that considers how the policy option of using federal programs to promote educational choice was proposed and debated in the 106th and 107th Congresses. This debate was part of the reauthorization of Title I of the Elementary and Secondary Education Act (ESEA) between 1999 and 2001. Over the past 20 years, Congress has debated numerous variants of private school voucher plans. The account demonstrates how the positions of the Clinton and Bush administrations, the 2000 presidential election, think tanks' advocacy of educational privatization, and public opinion shaped congressional action. The article explains why private school voucher proposals failed to pass in two consecutive Congresses, when the Republicans held control of both houses for three of the four sessions. The article draws on interviews with congressional aides and members of interest groups during the ESEA reauthorization process, and it applies John Kingdon's framework on agenda formation to explain the persistence of alternatives for privatization within Title I. The issue of school choice in Congress reveals the limits of the GOP's ideological unity--that is, that there could be demands from Republican Party leadership to include vouchers in Title I, but President George W. Bush chose to steer his party away from those demands.