At the end of the vice-presidential debate Thursday night, most objective pundits declared that Sen. Joseph R. Biden Jr. did better on substance but Alaska Gov. Sarah Palin was effective on style, approaching her poised performance in her convention speech.
Every objective national poll showed that more people thought Mr. Biden had "won" - whatever that means. I think that means he seemed more vice presidential. Can there be any doubt about that?
In fact, the post-debate polling data confirmed Mr. Biden had moved more persuadable voters than Mrs. Palin. The national Gallup Daily Tracking Poll had the Obama-Biden ticket at plus-five percentage points before the debate to plus-eight points as of Saturday night.
The simple answer, supported by most polls, is that Mr. Biden's articulation of his and Sen. Barack Obama's center-left positions on the major domestic and foreign policy issues have more support among voters than Mrs. Palin's accurate depiction of her and Sen. John McCain's conservative positions.
One way to understand why the polling data are showing these results is to look back in U.S. history to track the swings between liberal and conservative national governments: particularly, the reasons for and duration of those cycles.
In a 1949 essay, famous historian Arthur Schlesinger Sr. -- father of the even more famous historian Arthur Schlesinger Jr. - identified 11 such swings in American history (as of 1949). These were what his son described in his 1986 book, "The Cycles of American History," as "periods of concern for the rights of the few and periods of concern for the wrongs of the many."
The senior Mr. Schlesinger pointed out from George Washington's presidency in 1788 through Harry Truman's in 1947 that the objective in six of the periods was to increase democracy and in five to contain it. The average duration of the liberal-conservative cycle, at least up to 1949, was about 16 years.
For example, in the first four decades of the 20th century, the senior Mr. Schlesinger said, there were three such cycles: the Progressive Era, 1901 to 1919; the Republican conservative restoration, 1919 to 1931; and the New Deal Era of strong, progressive government under Franklin D. Roosevelt and Truman, 1931 to 1949 (which lasted through 1952, when the next cycle of center-right conservatism under President Dwight Eisenhower set in).
The pattern continued in the last half of the 20th century. But as communications and technology accelerated the flow of information -- especially in the 1990s, with the revolutionary impact of the Internet and 24/7 cable TV news -- the pace of change accelerated and the cycles shortened.
After the essentially status-quo quiet of the 1950s came the more government-activist center-left New Frontier of John F. Kennedy and the Great Society of Lyndon B. Johnson in the 1960s. Then came the intense Nixonian conservative reaction to Vietnam, urban riots and the counterculture - a right-wing backlash so severe that it triggered a conservative cycle that lasted from 1968 to 1992, from Richard Nixon to Ronald Reagan to George H.W. Bush (including Jimmy Carter, a center-right Democrat elected in the aftermath of Watergate by the narrowest of margins, and Gerald Ford).
In 1992 came Bill Clinton's center-left restoration, which, except for a few hundred votes in Florida and one more vote on the Supreme Court, could have lasted at least 16 years with two terms by former Vice President Al Gore.
But a true fiscal and social conservative president, George W. Bush, won about half the country in 2000 and a little more than half in 2004. (Preceding Mr. Bush was the historical conservative congressional revolution instigated in 1994 by House Speaker Newt Gingrich. The pendulum swung dramatically back 12 years later in 2006, when the Democrats took over both houses of Congress.)
These historic patterns are not coincidental, according to both Schlesingers. They reflect the ebb and flow of an American political culture and representative democracy system that, to its credit, mirror changes in public mood, if not immediately then reasonably soon after they have begun.
These political swings are not so hard to understand. Look no further than basic human nature. Problems accumulate, which trigger a desire for change to solve those problems. But then people get tired of being hassled by government, and a period of "leave me alone" conservatism sets in. Then problems accumulate again. And once again the pendulum wants government to take the lead in solving problems and controlling the excesses of the private marketplace. And so on.
So here we are in 2008. We should know the pattern by now and what to expect.
As Mr. Biden said during Thursday's debate, "past is prologue." Our problems, domestic and foreign, have accumulated (that's certainly an understatement) under conservative presidential and congressional rule over most of the last eight years.
And the pendulum has swung.
People are fed up. They want (you guessed it) change. And Mr. Obama brilliantly saw this and seized this ground before anyone else in either party and made it his own more effectively than anyone else.
Shock, shock: Issues matter, most of the American people are now center-left on most economic and foreign policy issues, ready for change, and are increasingly supporting the Obama-Biden ticket, which is closest to their views on the issues and the role of government at this point in history.
The pundits can relax. No need for more punditry over the next two presidential debates. The answers are in the history books. It's over.
The Democratic Obama-Biden ticket will win by a solid margin on Nov. 4, reflecting this inevitable rhythm in American politics going back to George Washington.
One caveat: The Obama-Biden ticket will win by a solid but not overwhelming margin unless Mr. McCain goes personally negative against Mr. Obama, as weekend press reports indicate. If he does, the Obama-Biden ticket will win by a landslide of historic margins.
Lanny Davis is a prominent Washington lawyer and a political analyst for Fox News. From 1996 to 1998, he served as special counsel to President Clinton. From 2005 to 2006, he served on President Bush's five-member Privacy and Civil Liberties Oversight Board. This article appeared in The Washington Times on Monday, October 6, 2008.