In the end, the most memorable line of the primary season may belong to Bill Clinton. He told a church group last month: "I've been waiting all my life to vote for an African-American president. I've been waiting all my life to vote for a woman for president. ... I feel like God is playing games with our heads and our hearts."

Hillary had barely celebrated her Code Blue victories in Ohio, Texas and Rhode Island before worries began to appear like a crawl across the screen during the victory party. A historic campaign could end up in a historic debacle.

Think back to those wonderful yesterdays when Republicans couldn't decide who to vote for because they didn't like their choices. Democrats were undecided because they liked their choices.

Now the worry is that the Republicans have sewn up their nomination while the Democrats are slogging off to the next battleground. While John McCain is saving his money and firepower for the election, Hillary and Barack will be wounding each other in Pennsylvania, Indiana, even Puerto Rico. While McCain can spend months uniting Republicans, Hillary and Barack will spend them dividing Democrats.

I understand the danger in the demographics. On Tuesday, Hillary won white women, older voters, working-class people and Hispanics. Obama won younger voters, African-Americans and the college-educated. I've been at enough tables lately where Democrats who usually side with each other against Bush now tensely size up each other's feminist credentials, antiwar loyalties or good sense. The good choices become hard choices accompanied by hard feelings.

But allow me to offer the contrarian view that "playing with our heads and hearts" has been a good thing, and the campaign may strengthen, not weaken the party's chances.

For openers, it's the "embeds" — the traveling press who look as weary as the candidates — and the party honchos who want it over. Two-thirds of the polled Democrats think it should go on.

A good part of the energy and excitement of this campaign comes — still — from having a woman and an African-American on the ballot. So far, Clinton and Obama have brought more voters to the polls than any primary campaign in recent memory.

A full 59 percent of the Ohio voters were women this year, up seven points from 2004. In Texas they were 57 percent, up four points. Obama engages younger voters. In Ohio alone there was a 10 percent increase in the under-30 vote compared to 2000. If it's good for Ohio, why not Pennsylvania? Indiana?

More to the point, this historic primary season hasn't just pitted one against the other, but changed the landscape for both. "Is America ready for a female president?" "Is America ready for an African-American president?" When was the last time you read either headline?

We've put to rest the question of whether a woman is tough enough to be commander in chief. Hillary's been the tough guy in the race. She has rewritten the common wisdom.

It's also put to rest the question of whether white Americans would vote for an African-American. In the whitest of states, such as Iowa and Vermont, Obama left the bias about bias in tatters.

As for the notion that these two candidates will mortally wound each other and limp into the race against McCain? Does anyone doubt that Obama is a better candidate now than he was last fall? Quicker on his feet? Sharper at debating? Better at responses? As for Hillary, does anyone doubt her resilience? She lost 11 primaries in a row and came back. Knock her down, she pops up.

Nobody wants to see Democrats writing the attack script for Republicans. If you think these two have been rough on each other, remember 2004, when Swift-boating became a verb. Primaries are training grounds. And if Tuesday taught us anything, the voters are not through deciding.

No, I don't want to see wrangling at the doorway to the convention. Nor do I want the bad feelings that can also come from calling the game before it's over. In the end, many of the dividing lines between gender and age are fault lines between mothers and daughters, husbands and wives. I'm betting they'll heal.

So to any Democrat gloomy over an extended fight, take a deep breath. Watch a rerun of John McCain, giving his joyless victory speech Tuesday night. There are many things worse than an extended race between history or herstory. You could get a Rose Garden endorsement from George W. Bush.

Ellen Goodman is a columnist for The Boston Globe. Reach her at ellengoodman@globe.com.