Ahmad Alush obtained permission from Swedish authorities last week to hold a protest outside the Israeli embassy in Stockholm on Saturday. He intended, he said, to publicly burn a Torah and a Christian Bible in retaliation for the burning of a Quran in front of Stockholm’s largest mosque last month.

The burning of the Quran on June 28 — for which Swedish police had also granted permission — set off a deluge of outrage. The governments of numerous Islamic countries condemned the action. So did the US State Department and the president of Israel. With tensions running high, Alush’s plan to set fire to copies of the Jewish and Christian scriptures was guaranteed to make an ugly situation even uglier.

But when the 32-year-old Alush, a Swedish resident of Syrian origin, showed up at the Israeli embassy on Saturday, he didn’t burn any holy books. Instead he tossed his lighter on the ground and announced that he never intended to carry out his threat. “As a Muslim, I don’t burn books,” he told the assembled crowd. His goal, he said, was to protest the Swedish laws that treat book-burning as a form of free speech.

“Burning the Quran is not freedom of expression, it is an action. Freedom of speech has its limits,” Alush insisted. “We have to respect each other; we live in the same society. If I burn the Torah, another the Bible, another the Quran, there will be war here. What I wanted to show is that it’s not right to do it.”

No, it’s not right to do it — civilized people do not torch or desecrate the sacred books of others. But that does not mean it shouldn’t be legal to do it. However depraved, hateful, or offensive such behavior may be, there is no question that it expresses an idea. And in free societies, the expression of even contemptible ideas must be protected. “In Sweden, you have the right to say almost anything you want,” the government website affirms, and the right to stage public demonstrations is guaranteed by the Swedish constitution.

For Americans, steeped in the culture of the First Amendment, the right to express even the most odious ideas is a core value as well. No element of our legal system “more imperatively calls for attachment than … the principle of free thought,” wrote Supreme Court Justice Oliver Wendell Holmes Jr. in 1929. “Not free thought for those who agree with us, but freedom for the thought that we hate.”

That is why the many voices that condemned Sweden for permitting the burning of the holy texts — from the chairman of the Swedish Islamic Federation to the European Jewish Congress — were wrong. As was the UN Human Rights Council, which by a 28-12 vote adopted a resolution urging member states to undertake “the prevention and prosecution” of those who advocate religious hatred. Punishing people who preach hatred on the basis of religion, or who would express that hatred by putting a match to a copy of the Quran or Bible, may seem a small price to pay to keep bigots out of the spotlight. But a government that can make the expression of anti-Jewish or anti-Muslim hatred a crime today can make the expression of other disfavored opinions a crime tomorrow.

As an observant Jew who reveres the Hebrew Bible, I agree without reservation that book-burning is uniquely barbaric. “Where they burn books,” the German playwright Heinrich Heine wrote with terrible prescience in 1821, “they will ultimately burn people also.” Heine’s works were among the tens of thousands of books torched in public bonfires by the Nazi regime after its accession to power in 1933 — and Hitler and his henchmen did indeed “ultimately burn people also.” So, in an earlier era, did the fanatics of the Inquisition who consigned “heretics” to the flames. So in our own time did the Al-Qaeda terrorists who turned the Twin Towers into an inferno.

Repugnant as book-burning is, however, I would not want to live in a society that would prosecute someone for buying a book and then torching it to express hatred or anger. Nor would I want to live in a society where someone could do such a thing without being widely castigated. They are two sides of the same coin: Hateful speech must be both vigorously protected by the government — and vigorously denounced by decent citizens.

Ahmad Alush, a Swedish Muslim, showed how to strike that balance. He established last week that he was free to burn the holiest books of Jews and Christians, then proved that he was wise enough not to do so.