The old adage says "the enemy of my enemy is my friend." But can the friend of my enemy be my friend?

As Republicans brace for what may be the most confrontational and possibly violent convention in 36 years - confrontational and violent outside Madison Square Garden, not inside - both parties are contemplating what will happen if anti-Bush protesters create a frightening atmosphere in New York.

Americans shy away from political conflict and punish politicians with hard edges and harsh rhetoric. That queasiness poses a challenge to those who have acquired the Bush-hatred bug this political season. Anti-Clinton zealotry on the right drove many independent voters to Bill Clinton during the '90s. And overwrought displays of emotional intensity by Bush haters could swing voters toward the president in 2004.

Protest organizers who understand this took the extraordinary step last week of holding a pre-convention news conference to assure New Yorkers that they come in peace. Still, according to media reports, activists plan to "follow some of the 4,853 delegates around town and harass them verbally and with leaflets at hotels, Broadway shows and parties."

Others plan to express their discontent by protesting with or without a permit, a sure route to the sort of ugly confrontations seen at anti-globalization demonstrations worldwide.

The protesters will come in all shapes and sizes, but from the same far-left ideological orientation.

Expect to see anarchists, Yippies (yes, the very same Youth International Party that radical Abbie Hoffman brought to the Democratic convention in Chicago in 1968), abortion-rights activists, union organizers, environmental extremists and maybe even some of those librarians who believe civil liberties have been taken away by the Patriot Act.

Their indictment of President Bush will include allegations that his environmental record is the "worst in history," that he's failed in the war against terrorism, that our economy is collapsing, that he hasn't "fully funded" the No Child Left Behind Act and that his tax cuts have benefited only "the rich" while his support for traditional marriage has damaged our civil society - hardly a recipe designed to attract moderates.

The stakes are high in this game of pre-convention positioning because, happily, ideas still matter.

The Democrats, after all, last month staged a carefully scripted convention that self-consciously emphasized mainstream and right-of-center values such as patriotism, a strong military, tax relief for small businesses and the "great" middle class, fiscal discipline and energy independence.

Many Americans nodded approvingly at Sen. John Kerry's embrace of these values. It's important that Mr. Kerry associate himself with these popular - and decidedly conservative - views. But if voters associate Mr. Kerry with the substance of the radical New York protesters, expect millions of independent voters to run, not walk, to President Bush and his more conservative agenda.

Democratic National Committee Chairman Terry McAuliffe insists his party has "nothing to do with the demonstrators." Not surprisingly, a spokesman for his Republican counterpart says, "They have been married for months and now they are pretending they have never met."

With that in mind, here are some challenges to the various entities:

• To the media: People don't travel hundreds of miles and devote considerable financial resources to protest frivolously. They do so only when they harbor strong passions and an alternative vision of the world. Explore the substance of that passion and ask the protesters to elaborate their vision. Most important, demand that they describe what they would do differently. We know they despise the president, but ask them to also evaluate Mr. Kerry on the issues.

• To Mr. Kerry and his campaign: If you sincerely believe these protesters have absolutely nothing in common with your values and policy positions, make that clear. Publicly distance yourself from the substance of the protesters' agenda. Ideas are the source and inspiration of the protests. It's not just street theater we will be watching, but street theater with a plot, a message and an ultimate goal.

• To Mr. Bush and his campaign: Don't attack the protesters as individuals, but assail their (potentially) lawless actions and invite a robust public debate on the views that drive them to such extremes. Commend them for their civic engagement (provided it remains civic), but be sure that every American watching at home understands the substance of the debate - what both you and they stand for and, of course, where your opponent stands.

If we're lucky this week, the streets of New York will offer us not a replay of the 1968 Chicago riots but a seminar as to what Mr. Bush and his passionate band of opponents intend to accomplish, how and why they differ and what, if anything, Mr. Kerry thinks of all this.

Michael G. Franc is vice president for government relations at The Heritage Foundation (heritage.org).