At least a quarter of all Americans are evangelical Christians, making them the nation's largest religious group — and one of its most influential. As religious conservatives, evangelicals champion family values and oppose abortion and gay rights, often using their considerable political power to try to bring about change. Some liberals and civil libertarians worry that evangelical Christians are trying to impose their beliefs on other Americans, and in the process are threatening to tear down the constitutional barrier between church and state. Meanwhile, some members of the evangelical community are calling for a withdrawal from the political arena. They say the only way to reverse the nation's moral decay is by encouraging people to lead a Christian life, not through political action.