A shifting political landscape could significantly affect the upcoming congressional review of the No Child Left Behind Act, even as states and school districts continue to grapple with the requirements of the nearly 4-year-old federal law. The law is slated for reauthorization in 2007, and that process is starting now, at least informally, as education groups poll their members for ideas, and policymakers consider proposals for change that have already been put forward. But all sides are peering into a murky future. The players and alliances surrounding the law's renewal are sure to differ in some ways from the lineup in 2001, when a bipartisan group of legislators hammered out the current provisions with the Bush administration. Even if the reauthorization is completed on President Bush's watch, some analysts and lobbyists say it will be hard for him to hold on to the law's core mission.