But there are broader lessons to be drawn. These rapid shifts are a warning to political commentators: Don't overinterpret a given political moment. While the ideological predispositions of most Americans are pretty well set, two factors still vary greatly from election to election -- ideological intensity and the support of independents. Both political parties have proved themselves capable of exciting their base, appealing to independents and securing decisive majorities -- and of squandering all these advantages quickly. At least in national politics, no future political outcome is predestined by current trends, demographics or other tools of tarot punditry. The Carville-like book of political predictions is a roulette guess, black or red. Either party can dominate -- or fail.
These swings also hint at a deeper dynamic. The velocity of political change seems to be increasing, propelled by information technology and a breathless, polarized media. Political time has become compressed. The interval between hero worship and humiliation has narrowed. The pace of disillusionment has quickened. Americans, along with Thomas Jefferson, may like a little rebellion now and then. But indulged too frequently, the habit seems more like instability. And the world is left to wonder about the consistency, even the coherence, of American economic and foreign policy.
Above all, this recent history should provide lessons for the winners. Even decisive victories are fragile. Majorities are built with the support of both partisans and independents. Results are ultimately more important than purity. Ideological overreach provokes a backlash. In the current case, there is a genuine uprising in favor of fiscal responsibility and job-creating growth -- but there is no mandate for the deconstruction of the modern state. The first revolution will be hard enough.
Following a large political victory, however, it is easier to drink deeply and dream. Which makes it likely that someone will write: "The Permanent Tea Party Majority."