The overwhelming majority of Americans once were Protestants, but church membership has been dropping for decades. Today, religious diversity reigns, with Protestantism only one among an array of American faiths. But declining numbers haven't dimmed church leaders' efforts to influence public issues, just as early Protestant churches drove social movements from abolition and Prohibition to the civil rights struggle. Some progressive political groups are linking up with so-called mainline Protestants like Methodists and Presbyterians to push for gay rights and anti-poverty programs. And conservative evangelical churches continue to speak out against gay marriage and for closer ties between the federal government and the Christian faith. But with the death this year of some old-guard conservative ministers, including Jerry Falwell, the evangelical agenda is being shaped by a new generation, some of whom want to add traditional liberal issues to the policy mix, like the environment.