PROTESTERS AT the Democratic presidential convention in Boston were kept in "free speech zones" -- cages, really -- that were so constrained and remote from delegates that most protesters avoided them altogether. At the coming Republican convention in New York, things will be a little looser, as a consequence of a federal court ruling, but only a little. And plans for a large antiwar demonstration in Central Park have been stymied by the city's refusal to issue a permit. Officials initially said they feared damage to the park's Great Lawn and more recently have cited safety concerns. They instead have offered protesters a stretch of the West Side Highway, which they first accepted and then rejected; the matter landed in court yesterday.

The city's gardening concerns seem frivolous, and the protesters ought to be able to use the park; the security concerns behind many of the restrictions are more serious. Terrorism fears are legitimate, and some of the protest groups include people with histories of violent behavior at demonstrations. The First Amendment does not give protesters the right to disrupt proceedings. Certain restrictions are necessary and appropriate.

But something precious is threatened when demonstrators -- even rowdy, obnoxious and possibly misguided demonstrators -- are kept at such distance from the objects of their protest. What's at risk is democracy, and it deserves a bit more respect. As has been widely noted, the parties now try to shape their conventions as extended infomercials, in which the forms of party process are playacted to validate preordained results. City police should not be deployed in a fashion that ensures that the infomercials do not suffer from any technical glitches, unruly moments or dissonant voices. This may not be the intent of the security measures, but marginalizing dissent is the effect. Somehow, even in an era of terrorism, America needs to do better.