The Capitol (J. Scott Applewhite/Associated Press)

Is America entering a new “cycle of history” — the pattern of oscillations in American politics between liberalism and conservatism identified by historian and Kennedy aide Arthur Schlesinger? In Schlesinger’s view, America, since its founding, has maintained a tension between pragmatic, secular liberalism and messianic, religious conservatism. Our politics has swung between the two: When the national mood favors a focus on public purpose, liberals are ascendant; when citizens grow weary of activism, they trend to private interests and conservative rule.

This admittedly broad view of political history is still useful in making sense of the current political scene. In my view, more than three decades of conservative rule are on the verge of ending and we are about to enter, in Schlesinger’s view, a “more liberal phase.” To some, this conclusion may seem strange. After all, what about Bill Clinton and Barack Obama, who served equal terms as conservatives Ronald Reagan and George W. Bush? Can we really say we have been living consistently in a conservative phase of the cycle? Yes, because the liberal sails of Clinton and Obama were dramatically trimmed by the conservative orthodoxy of the day. Bill Clinton famously governed from the center-right, was pro-death penalty, favored welfare reform and opposed gay marriage. He declared the era of “big government” to be over. Despite much of the right’s fevered imagination, Barack Obama also has governed conservatively. His signature health-care reform was born in the Heritage Foundation. And he preserved the status quo by bailing out Wall Street and  failing to take an activist’s hammer to the financial services industry in the wake of the financial crisis.

Two factors have primarily been responsible for the long conservative reign in America. First, the strong alliance in the Republican Party between social and economic conservatives; and, second, the deep fear of terrorism engendered on Sept. 11, 2001. But the former is crumbling, and the latter is fading. The country is moving quickly and dramatically to more liberal positions on gay marriage, abortion, immigration and even marijuana, where a majority of Americans, according to a recent poll, now favor legalization. So the economic conservatives no longer have a reservoir of social-issue conservatives to count on. And the shock of 9/11, which made most domestic concerns subordinate to homeland security and which led to massive increases in the defense budget, has abated. We are debating civil liberties again and cutting the defense budget.

The national mood is changing and accelerating toward favoring a more pragmatic (or libertarian) approach to private lives and a more activist one to public life. The economy is flat; income disparities are at a record and, I would argue, politically unsustainable level; and the millennials, while they may eschew traditional public service, are actively engaged to in trying to improve their communities. All these factors are setting the stage for the cycle to turn.

Which political party may benefit from this shift is unclear. Democrats should, but they have been so cowered by conservatives for so long that they may fail to sense the opportunity. Ironically, tea party Republicans stand to benefit as well, if they can restrain their nihilist impulses. They certainly have the populist angle on some economic matters, but their obsession with the federal debt will mute their effectiveness.

We are clearly in a time of transition, where the alliances and political coalitions born with Nixon and fully realized under Reagan are breaking down. Where will the new political fault lines fall? And which political party will take full advantage of the new landscape?