Dean E. Murphy, in the NYT (Nov. 7, 2004):

A LITTLE more than a month before he was assassinated, Abraham Lincoln stood at the east portico of the Capitol and delivered his second inaugural address. It was a brief speech with a distinctly religious message: he twice cited biblical verses, and made a dozen references to God, most strikingly in assessing the opposing sides in the Civil War.

"Both read the same Bible and pray to the same God, and each invokes His aid against the other," Lincoln said. "It may seem strange that any men should dare to ask a just God's assistance in wringing their bread from the sweat of other men's faces, but let us judge not, that we be not judged. The prayers of both could not be answered. That of neither has been answered fully. The Almighty has His own purposes."

The address was roundly criticized in some newspapers for overstepping the bounds separating church and state. But Lincoln was using God to debunk government-by-God.

Now, with George W. Bush's re-election, God and a newly triumphant Republican president are once again in the headlines. And there are signs that the present national divide, between the narrow but solid Republican majority and a Democratic party seemingly trapped in second place, may be hardening into a pattern that will persist for years to come.

Democrats, especially, are left to wonder: What will it take to break the pattern - an act of God?

History suggests several possibilities for a major reshaping event - a national calamity, a deep schism in the ruling party, the implosion of a social movement under the excesses of its own agenda or the emergence of an extraordinary political figure.

Lincoln became president and the Republicans first took national power when the Democrats tore themselves and the nation apart over slavery and secession. Another national trauma, the Great Depression, produced a sweeping realignment in favor of the Democrats and Franklin D. Roosevelt.

Religious revivals and movements have also gusted periodically through American politics, sometimes reshaping the landscape as they go, said Susan Jacoby, author of "Freethinkers: A History of American Secularism." But she said it was not easy to find a historical blueprint for the current situation, with the religious right forming the core of Mr. Bush's majority.

The closest parallel, Ms. Jacoby said, might be the Christian temperance movement. It eventually "defeated itself," she said, with the absolutism of Prohibition, which spawned outlandish bootlegging and crime problems and made lawbreaking fashionable. The Depression eventually pushed joblessness and poverty ahead of temperance on the social agenda.

Even so, Ms. Jacoby said, that religious-political movement, smaller than the one swelling behind Mr. Bush, took decades to play itself out, and was not linked to a single party, as the Christian right is now. "What we have today is an unprecedented situation in American history, in terms of the willingness of a large number of people, backed up by the president, who want to infuse more religion into government," Ms. Jacoby said.

Sean Wilentz, a professor of history at Princeton, saw two instances in history when the American electoral landscape resembled that of today. "They are kind of scary examples," Professor Wilentz said. "One is 1860, and we know what happened after that one, and the other was 1896, the McKinley-Bryan election."

That contest, which seemed to herald a new era of Republican dominance, also started a chain of events that led to a disastrous schism in the party. William McKinley, a conservative Republican, defeated William Jennings Bryan, a populist Democrat, and won the first clear popular majority in 24 years. He beat Bryan even more soundly in 1900, but less than a year later, he was assassinated.

His death was a tragedy and a fluke, Professor Wilentz said, but it changed the course of political history. Had McKinley not been killed, Marcus A. Hanna, the political handler who was as instrumental to McKinley's success as Karl Rove has been to Mr. Bush's, would have pursued his dream of "creating a Republican machine that would go on forever," Professor Wilentz said.

Instead, Theodore Roosevelt became president, and pursued progressive policies at home and power projection abroad. "What followed shifted the Republican Party in a direction it had not planned to go, and created the groundwork for 1912 and eventually the New Deal," Professor Wilentz said. When his successor, William H. Taft, turned back to conservatism, Roosevelt ran against him in 1912 on the Progressive, or Bull Moose, ticket, and split the Republican Party, yielding the White House to the Democrats and Woodrow Wilson.

"One can't imagine what American history might have looked like had McKinley continued to the end of his second term," Professor Wilentz said.

Similarly, George Wallace stormed out of the Democratic Party in the 1960's over desegregation and states' rights, and took many conservative Southerners with him, weakening the party's hold on a region that has since turned solidly Republican.

A split like those could happen again. The war in Iraq could become so unpopular that it would dog Mr. Bush and the Republicans the way that the Vietnam War did President Johnson and the Democrats....