It’s only hours until 2008. For months now, that date has symbolized choice and change. National elections come only once every four years, and elections like this one, with no presidential incumbent nor presumptive nominee, are very rare. We’ve had only three in the past century.

So the country is about to row out into the future, without the usual buoys. We’re entering a new year and making decisions about a new direction and a new age. New Year’s Eve is traditionally a night of revelry. What we need the day after is sobriety. We’re about to choose a man or a woman to lead us into the uncertainty ahead. But this time the choice is more significant, potentially more enduring.

For a third of a century there has been a man named Bush or Dole on the Republican national ticket. For the first time since 1972 – unless the GOP nominee chooses former Gov. Jeb Bush of Florida as his running mate – the Republicans will be setting a new course. If the Democrats nominate Sen. Hillary Rodham Clinton of New York, they will of course be breaking new ground, but it still will be the case that in every election since 1980 there will have been a Clinton or a Bush in the general election.

That said, there are unknowns ahead. Some of them are obvious, like the nation’s commitment to the struggle in Iraq, or the nature of the national health-care system – every candidate has a version in mind – that will replace or supplement the rickety one we have now. But some of the questions that face us are more subtle and, as a result, potentially more enduring. Here are some of them:

¢ Will the winner (or, just as important, the loser) of the general election set his or her party on a dramatic new course? Franklin Delano Roosevelt put the Democrats on an entirely different footing after his election in 1932, and in some important ways the nation still is affected by the choices voters made that year – in a different America in difficult circumstances.

But it is also true that the landslide losses of Sen. Barry Goldwater of Arizona in 1964 and Sen. George S. McGovern of South Dakota in 1972 had profound effects on their parties and on the country. Goldwater’s candidacy was but the opening gambit of a new kind of muscular, confident conservatism that prevailed under Ronald Reagan in 1980 and was refined under George W. Bush in 2000. McGovern’s candidacy sealed the Democrats’ identification with racial minorities, women and a curator state that was repeatedly repudiated by voters – but that is not unfamiliar in the camps of today’s three leading Democratic presidential contenders.

¢ Are the parties readjusting their profiles? In a dramatic new interpretation of American political history, Brandeis University scholar Morton Keller points out that modern Republicans stand in opposition to the religious separatist, social reformist, trade protectionist and anti-states’-rights Republicans of the 19th century, while modern Democrats have turned away from the states’-rights, small-government, white-supremacist, free-traders who marked the party three generations ago.

Parties don’t stand still. In the past century, the American parties have performed a do-si-do that is dizzying. The Democrats, who once had the allegiance of evangelicals, have rediscovered God. They may have done it too late to recapture evangelicals but just in time to recapture the observant Catholics and mainline Protestants whom George W. Bush won by huge margins in 2004 – and who, according to Pew Research Center findings, are now far more likely to vote for a Democrat than for a Republican.

¢ Is the country ready to seek a new approach to the role of government in society? The New Dealers under FDR looked to government solutions for the Great Depression. The Great Society under Lyndon B. Johnson embraced government to redress the grievances of the poor, the striving, the sick and the dispossessed. The Reagan conservatives looked askance at big government and began to regard Washington as the problem, not the solution. The result was that there was a Democratic approach and a Republican approach.

Then the two baby-boom presidents, Bill Clinton and George W. Bush – born within weeks of each other in the summer of 1946, the first year of the boom – came along and messed everything up.

Mr. Clinton, reeling from the Republican takeover of Congress in 1994, declared the era of big government over. Though his liberal allies howled, it was political necessity. Mr. Bush, reacting to the terrorist attacks of 2001, presided over a huge increase in federal employment and expenditure, partially in the military, partially in homeland defense. Though his conservative allies howled, it was national-security necessity.

Now the nation faces an important philosophical moment that no one wants to confront – not when social problems persist, not when terrorist threats remain. The country lacks a coherent notion of what government should do, what the markets should do, what charitable institutions and nonprofit organizations should do.

¢ When does the United States intervene abroad and when does the country engage in nation-building? Both parties have delivered mixed messages over the past 16 years. As a result, the U.S. philosophy in foreign affairs is unclear and uncertain. That is all right in a nation like Bulgaria or Paraguay. It is not acceptable in a superpower. The world expects more, and it deserves more. The new year is a good time for a new approach.