THE CHOICE in Tuesday's Democratic presidential primary is not only the one between a white woman and a black man. It's a choice between the past and the future.

More specifically, the nation must decide how to face the future racing toward us in the form of slumping home sales, unstable financial markets and increased joblessness – and staring at us from the Green Zone in Iraq and the beds at veterans hospitals.

Should Democrats choose someone who will employ hard-won – even bitter – experiences gained in a past Democratic administration, or reach beyond political truisms toward a new (and untried) model of governing?

Neither choice is obvious. Perhaps that's why the race has gone on for so long.

But the long slog through 44 primaries and caucuses has confirmed for us that Sen. Barack Obama's vision of change – and the way he plans to pursue it – is what we need right now. Badly.

This is a campaign that really began six years ago, on Sept. 11, 2001. Not only was the U.S. attacked and seriously wounded, it did not bounce back the way “the land of the free and home of the brave” should have. In fact, it still suffers from post-traumatic stress.

That day and its aftermath cried out for a revolution of values: a clear-eyed shared vision, a cooperative effort, a unified purpose. It cried out for a recognition that conventional warfare and conventional responses to domestic challenges in an era of globalization were not enough.

That cry was not answered.

Instead, the Bush administration embarked on an unconscionable plan to exploit the fear we all felt that day for political gain. It lied us into a disastrous war in Iraq, a staggering, record deficit at home, a weakening of the constitutional structure on which the country rests, and poisonous lines of division among Americans. It led us to a place where 81 percent of Americans say we're on the wrong track.

Contrary to Sen. Hillary Clinton's campaign slogan, we believe Barack Obama is more likely to be “ready on Day One” to lead us in a new direction. Because of his experience.

Sure, Clinton has more “experience” of a sort. For one thing, she has 14 more years on earth. How much of this experience is directly applicable to the job of president is, at best, debatable.

We are frankly troubled by her assumption that her husband's administration and accomplishments were her own. And if her equation holds, that the first spouse is an equal partner in the administration, then the reappearance of Bill Clinton in the White House is a prospect we have a hard time reconciling with the work that needs to be done.

THERE IS a way to match Clinton's and Obama's performances on a relatively equal playing field: their campaigns.

A candidate's campaign may be the best indicator of how she or he will govern. If so, an Obama administration would be well-managed, inclusive and astonishingly broad-based. It would make good use of technology and communicate a message of unity and, yes, hope.

It would not be content with eking out slim victories by playing to the narrow interests of the swing voters of the moment while leaving the rest of the country as deeply divided as ever. Instead, an Obama administration would seek to expand the number of Americans who believe that they have a personal stake in our collective future – and that they have the power to change things.

It would motivate them to hold their representatives accountable for making it happen. That is, after all, the only way to get us out of Iraq, to address global warming, to make us energy-independent. It's the only way to resist the forces arrayed against providing universal health care, rebuilding our infrastructure and returning our schools to world-class status. It's the only way to give our children the means to compete with children in other parts of the world who are healthier, better-educated and have more opportunities than many of our own.

An Obama administration would be freer of the the corrupting influence of big-money donors and corporate interests. Obama has raised $240 million overall, with half coming in contributions of less than $200. People who contribute to political campaigns can feel they “own” a candidate and so Obama would owe allegiance to the wide swath of America that has financed his campaign.

Based on his experience in running a quarter-billion-dollar enterprise with thousands upon thousands of volunteers, we could expect an Obama administration to be well-managed and cost-effective, with the president choosing forward-thinking advisers committed to his program, demanding that they work as a team and pay attention to details.

He would be steady and calm, given neither to irrational exuberance or outbursts of anger. He would make mistakes, that's for sure, but he could be expected to recognize them, adjust, and move forward.

He would adjust his views to reality rather than trying to adjust reality to his views.

Obama's unprecedented appeal to younger voters is significant not only because it expands the electorate, which is vital. It's also a validation of his promise as a president to be free of the baby-boomer/Vietnam/segregation-era hangups.

Younger people are more egalitarian, more accepting of diversity, and more comfortable with rapid change. They also are less confined by old resentments or regrets.

AND AN OBAMA administration would lower the tone of the rhetoric that separates us.

As New Mexico Gov. Bill Richardson has said, Obama is a once-in-a-lifetime candidate who has the skill and eloquence to help us raise our eyes and our aspirations beyond individual, personal concerns, beyond religion or region or race or gender, beyond our well-founded fears to a shared destiny.

Most candidates claim that they will change the way business is done in Washington. Barack Obama has made us believe that, yes, he can.

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GO BARACK! ROCK THE PENNSYLVANIA VOTE!