A glance at our Letters page in the past few weeks makes clear that the controversial ads on Chapel Hill Transit buses are the First Amendment in action.

And, regardless of whether you happen to agree or disagree with the message in those ads, from where we sit, that is something to celebrate.

The First Amendment exists in order to encourage the free and open exchange of ideas, even – no, especially – ideas that some people disagree with or find offensive.

That is exactly what’s happened with the bus ads. The ads, sponsored by the Church of Reconciliation, urge an end to U.S. military aid to Israel.

In our pages, at Town Council meetings and elsewhere, that message has sparked a vigorous debate. That’s what’s supposed to happen in a free society. That’s your First Amendment dollars at work.

We encourage everybody to be respectful and civil in making their points, because that’s much more conducive to productive conversation, but it doesn’t always work out that way. The public discourse has not always been polite.

But that’s the price we pay for freedom of speech, and it’s a price we – speaking editorially here – are willing to pay.

Not everyone is. Some folks, including some Town Council members, have called for the ads to be removed because they find them offensive.

That complaint gets to the very heart of what the First Amendment is all about. You can’t simultaneously embrace the concept of freedom of speech and also protect people from being exposed to ideas that might offend them.

If the First Amendment only applied to speech that didn’t offend or upset anybody, well, we wouldn’t need it. “I defend your right to speak your mind, but only if you agree with me” isn’t much of a principle. The only speech that needs a First Amendment is speech that some folks find disagreeable. Like those ads on the buses.

The ACLU last week made a well-reasoned argument that the town cannot constitutionally remove the ads.

Chapel Hill’s own policies and practices of allowing ads on buses have clearly established that buses are “designated public forums,” which means the government has limited legal power to restrict speech in them.

In particular, the government cannot restrict ads based on the particular viewpoint expressed in them. In other words, the town cannot legally allow ads it agrees with and prohibit ones it doesn’t.

And because the only objections anyone has raised about the Church of Reconciliation’s ads are based purely on the viewpoint the ads express, the ACLU argues, the town would face an insurmountable difficult legal hurdle if it pulled them now.

We think the ACLU makes a convincing case. And aside from the legal argument, there’s the cultural one: Chapel Hill is, according to its own website, a town that prizes diversity and “the free exchange of ideas.” Those are values we embrace. We hope the town sticks to them.