Robin W. Lovin is the Cary Maguire University Professor of Ethics at Southern Methodist University:

The Democratic Party managed to lay claim to some core values in American political life this week. In the process, it may have made an important change in its own political rhetoric.

Some Democratic strategists have been wary of issues charged with religion and ethics, and the message from Boston to undecided voters clearly was supposed to be that John Kerry is ready to be commander-in-chief. Nevertheless, it's hard to have a national convention without giving your core supporters some reason to cheer about being who they are, and the words that made a difference in the hall delivered a powerful message to the rest of the country, too. The electric moments in the week came when Jimmy Carter told the delegates that America needs to stand for something in the world, John Edwards told them that no one who works at a job should live in poverty, and Al Sharpton told them that they were the party of civil rights and social progress for African Americans. John Kerry's masterful summary of these themes in his acceptance speech on Thursday night resolved any questions about whether these values issues were "on message" for the convention and the campaign.

Those are themes that need to be heard at a time when talk about values in politics often seems to refer to issues of family life and personal choices. The values that were articulated in Boston are important because they are genuinely political. They deal with goods that can only be achieved through legislation, government, and diplomacy. They are not primarily about moral choices people make in their own lives, but about moral choices that we have to make together: What price will we pay for security? What restraints will we put on power? What opportunities will we insist belong to everyone?

The Democratic Party has been reluctant to treat these as questions about values, in part because it has been more successful in recent years treating them as questions about interests. Bill Clinton was the great master of this, and he demonstrated his genius again on Monday night. Beginning with an ironic admission that he now finds himself, unexpectedly, the beneficiary of tax cuts for the wealthiest Americans, he asked his audience to decide whether they wanted to sustain his tax cut or have real prescription drug benefits for the elderly, to sustain his tax cut or have more police on the streets, to sustain his tax cut or provide funding for children and at-risk youth.

When you have an audience that likes to identify itself as middle class and thinks of itself as working for a living, you can ask them to choose some core Democratic values by asking them to think clearly about their own interests. You can even talk about war and peace by asking how they want decisions made that may put them or their children in harm's way. Republicans are apt to deride this political strategy as class warfare, but the issues it raises are real, and the strategy makes the opposition nervous because it works.

So why not be realistic? Why not just stick to interests and leave values out of it? One reason is that interests, if that's all they are, are divisive. There's a difference between a very broad coalition of interests and a genuine common good. It was Saint Augustine, the first great political realist, who said that without a commitment to love and justice, there's no difference between a state and a band of robbers. You can get elected by defining interests cleverly, but a coalition of thieves is hard to govern. You need values to govern.

Of course, the values that truly make us a nation are, almost by necessity, values that we share. They don't lend themselves to defining "us" against "them." In today's global society, they don't even define us against other nations, though they may help explain why nationhood and self-determination are so important that their absence can lead to a nihilistic spiral of violence that denies all values. Barack Obama's keynote address on Tuesday evening was a powerful evocation of the United States of America and its meaning for the world, instead of the trivial punditry of "red states" and "blue states" that dominates the airwaves as we approach November 2. Unfortunately, the major television networks decided that nothing important was happening on Tuesday evening, but Obama identified himself to those who were able to hear him as someone with a capacity for leadership as well as strategy. He provided some crucial themes for the convention and for Kerry's own acceptance speech, and those who missed Obama this time can be sure he will be heard from again.

The problem for politics, however, is that it is difficult to win an election on values that have to be shared with the opposition, too. No one is likely to become president on values alone, though it might be possible to lose the election on them, if people come to believe that a candidate doesn't understand what holds our national life together, or doesn't care enough about it, or is just too quick to sacrifice it for short-term gains in security and power. Paradoxically, a campaign about values has high potential for becoming a negative campaign, and Kerry wisely used the only direct reference to George Bush in his speech to warn against that possibility.

For the next 90 days, the realists are going to be thinking mostly about red states and blue states and trying to figure out exactly what interests will motivate that small but decisive percentage of voters who haven't already made up their minds. For those purposes, the image of John Kerry surrounded by crewmates from his Swift boat no doubt conveyed an essential message. If you're not sure who to trust with the all-important interest of your own security, the image said, this guy will take care of you. If you want to know who's looking out for you, this guy will do it.

We can't blame the strategists for wanting to get that message out. That's part of what conventions are for. But if the election strategy works, it's those other words and ideas about values that will make the difference in the governing that follows.