Welcome to the new America.

I’m not talking about a blue America or a red America. I’m talking about a 21^st century America – a nation of many colors, cultures and faiths.

Barack Obama’s election as the first African-American president symbolizes what we have known for some time, but often fail to acknowledge: The United States has become one of the most religiously and ethnically diverse societies on Earth.

Today, for example, only half of the American people identify themselves as Protestant – a stunning shift in this historically Protestant nation. There are now more Muslim Americans than Episcopalians, the church of many of our Founders.

By mid-century, the Census Bureau tells us that we will be a “minority majority” nation in every sense of the term – a demographic milestone with far-reaching social and political implications.

That’s why a high priority for President-elect Obama isn’t only the economy or the two wars, but also the urgent need to unify Americans and develop a common vision of the common good across our differences.

That will not be easy. In the wake of the longest presidential race in history – an often bitter campaign that exposed our ideological and religious divisions – Americans are angry, partisan, and emotionally spent.

Nevertheless, at this difficult moment in our history, we have no choice but to come together. Those obligatory post-election calls by both candidates for “national unity” need to be translated into actions that transcend our racial, religious and ideological divisions.

The new president must persuade fellow Democrats to resist the winner-take-all mentality, just as John McCain must encourage Republicans to eschew guerrilla warfare. Our current challenges are too big, the stakes too high for politics as usual.

Of course, extreme voices from the left and right – especially the Internet flame-throwers – will continue to debase the debate. Incendiary rhetoric, name-calling and similar tactics will still pollute the public square, undermining efforts to find common ground.

But that may not work so well anymore. In this election cycle, negative ads, especially personal attacks, triggered a backlash among many voters. And some of the familiar culture-war bullies were relegated to the sidelines where few people paid attention.

A defining moment, for me at least, came in October, during Gen. Colin Powell’s appearance on NBC’s “Meet the Press.” After condemning scurrilous attempts to link Obama with terrorism by accusing him of being a secret Muslim, Powell added this: “But the really right answer is, What if he is? Is there something wrong with being a Muslim in this country? The answer’s No, that’s not America.”

Powell then described a photo he saw of a mother in Arlington Cemetery with her head on her son’s grave. “And as the picture focused in, you could see the writing on the headstone. And it gave his awards – Purple Heart, Bronze Star – showed that he died in Iraq, gave his date of birth, date of death. He was 20 years old. And then, at the very top of the headstone, it didn't have a Christian cross, it didn't have the Star of David, it had crescent and a star of the Islamic faith. And his name was Kareem Rashad Sultan Khan, and he was an American …. He was 14 years old at the time of 9/11, and he waited until he can go serve his country, and he gave his life.”

Powell’s poignant comments were not only about the need to respect the rights of Muslim Americans, as important as that is. He was also making a larger point about what it means to be an American.

In this new America, we can no longer afford to define “American” along racial, ethnic or religious lines – a mistake we have made time and again in our history. To be an American is not about the color of your skin or where you worship. It’s about upholding guiding principles such as racial justice, equal opportunity and religious freedom that bind us together as “We the People.”

E Pluribus Unum – out of many, one – is more than our national motto: It’s an urgent challenge for the new president, and for us all.

Editor’s note: Charles C. Haynes is senior scholar at the First Amendment Center, 555 Pennsylvania Ave., N.W., Washington, D.C. 20001. Web: firstamendmentcenter.org. E-mail: chaynes@freedomforum.org.