The issues of race and gender have a long and prominent presence in American history, especially when linked to the civil rights of women and blacks.

It has also been a divisive and troublesome presence, one that the two leading Democratic presidential contenders — a woman and a black — are trying to keep from contaminating their campaigns.

"Neither race nor gender should be a part of this campaign," Hillary Clinton vowed at the beginning of Tuesday's debate in Las Vegas.

She's right: Voters should choose between her and Barack Obama — or the other candidates — on the basis of their qualifications, policy positions and vision.

Given the strength of both, it's hoped Clinton and Obama have made race and gender politics irrelevant at last.

But it's easier said than done. It seems impossible to ignore the unique nature of their candidacies and how they fit into the context of U.S. history.

When Oprah Winfrey tells the crowd in Columbia, S.C., that "we don't have to just dream the dream anymore. We get to vote that dream into reality. I believe that now is the time for somebody like Barack Obama," she's talking about the candidate's race.

And when Clinton goes on "Meet the Press" and defines herself as "a woman running to break the highest and hardest glass ceiling," she's using the language of gender politics.

Between now and Super Tuesday, Feb. 5, we can expect the candidates to take the gloves off in their struggle to gain the momentum. That's politics, and there are plenty of real issues to argue about: the economy, Iraq, the environment, just to name a few.

We should expect that the candidates and their supporters set aside those academic questions: Are we ready for a black president? Can a woman be commander-in-chief?

As a nation, surely we've outgrown the need to ask.