The original Tea Party was neither a political organization nor a populist movement. It was a one-night stand, an evening uprising. Nevertheless, the young John Adams judged it so intrepid and consequential as to mark "an epocha in history."

The British government agreed. Lord North warned the Commons that a turning point had been reached. "We are now to establish our authority," he said, "or give it up entirely." We all know how that turned out.

Both the old and the new Tea Party stand for resistance to unconstitutional power. In 1773 the Tea Partiers opposed the Tea Act, which violated their rights as Englishmen and as men. Their counterparts today fight against Obamacare, a much worse law. And they have enough orneriness left over to confront many other usurpations by the Obama Administration as well as several inherited from Bush II.

Modern liberalism can neither fathom nor tolerate the Tea Party. Liberals don't believe in a right of revolution against liberalism. They consider progress as they define it to be irreversible. For example, here is Barack Obama at his most peremptory, calling in 2009 for nationalized health care. "I am not the first president to take up this cause," he told Congress, "but I am determined to be the last."

As liberals see it, conservatism's job is to conserve liberalism. When it threatens to overturn a program like Obamacare, then the Right ceases to be conservative and becomes radical, indeed revolutionary insofar as it threatens not just a cabinet department or two but the whole religion of one-way leftward progress and the whole worshipful establishment built around that faith.

Even a smart liberal like Sam Tanenhaus considers the Tea Party to be the last gasp of a dying conservatism that has ceased to be Burkean and become, in his word, "Jacobin," that is, revolutionary in the bad, French sense. Of course, the Tea Party's very name refers to a revolution—but to the American Revolution, not the irrational French one. Tanenhaus doesn't see much of a difference because he seems to dismiss as extremist any form of politics that doesn't go with the evolutionary flow, and that appeals to universal and timeless principles of justice. One is tempted to say that he rejects natural rights as firmly as John C. Calhoun did and for a similar reason: they endanger the ancien regime, which in our time is liberalism.

If the Tea Party is revolutionary, it is so only in the traditional American sense: it wants to revolve back, to return to the Constitution and the principles of the Declaration of Independence as the basis of government. This is the deepest reason why the Obama Administration has reacted to this Tea Party as Lord North did to the original. If Obamacare is overturned, then liberals will have lost control of the future and hence of their legitimacy; and if they lose the future, they will lose the present, too. So the Tea Party must be stopped at all costs.

* * *

Liberals like to denounce the Tea Party as inherently "dysfunctional," which in translation means: it stands athwart History yelling Stop! The whole conservative movement since William F. Buckley, Jr., is dysfunctional for the same reason. The Constitution itself is dysfunctional—full of institutions like checks and balances, bicameralism, the separation of powers, and federalism designed to temper hope and to slow political change, to force time for deliberation and due process, to conserve the people's loyalty to the Constitution and laws.

What the battle over Obamacare has helped to reveal is that it isn't just two clashing interpretations of the same Constitution that divide liberals and conservatives today. It is increasingly two different constitutions that are locked in conflict. Liberals support the "living constitution," which regards the bulk of the 1787 document as dysfunctional under modern conditions, hence obsolete if not, indeed, dead. They recognize only a few phrases in a few amendments as truly vital.

Conservatives cling to the old Constitution (as amended) not merely because it is old but because its principles of justice, based in human nature, are correct, and because its institutions and customs wisely anticipate both human greatness and human baseness. From this point of view, it is the passage of Obamacare—with its hasty party-line votes, corrupt side-deals, and brazen lawlessness—and not its attempted repeal, that amounted to a constitutional dysfunction.

Both the Tea Party and the Obama Administration understand the stakes. But it will take a lot more than an evening's Tea Party to win this struggle.