The tea party movement has been nearly invisible in the intensive lobbying campaign over the “fiscal cliff,” even as Congress and the White House debate the issues of government spending and national debt that are at the core of the movement’s identity. In many ways, the tea party was made for this moment. The grass-roots opposition to President Obama’s agenda that arose in 2009 has been so focused on fiscal concerns that leaders once prevented speakers at tea party rallies from even discussing abortion and other social issues. And in fact, it is the tea party that helped bring the...