The writer, a former Soviet dissident and retired mathematics and physics teacher, is a member of the board of the Andrey Sakharov Foundation.

Disaster has struck my home. A month ago my son, Dima Litvinov, who is 51, was jailed in the city of Murmansk, Russia, north of the Arctic Circle.

Dima has the sad distinction of possibly becoming the third generation of political prisoners in our family.

The photos of him handcuffed and then in a steel cage were seen worldwide. He is a part of Arctic 30, a group of Greenpeace activists that is composed of two journalists, a doctor, a cook and other members of the crew of the Arctic Sunrise icebreaker. They represent 18 countries. Dima and the ship’s captain, Pete Willcox , are the only Americans.

Dima was born in Russia and, at age 6, joined me in a Siberian mining village where I was sentenced to exile and labor. He spent four years there with me. After that, we were forced to emigrate from Russia, and Dima grew up in the United States. He graduated with bachelor’s and master’s degrees in anthropology from Wesleyan University. In the 1980s, he joined the environmental organization Greenpeace.

Being fluent in his native Russian, he was invited to be an interpreter in the first Greenpeace action aimed at the arctic island of Novaya Zemlya, where the Soviet government buried nuclear waste from years of weapons testing. Soviet authorities took the Greenpeace activists, including Dima, to Murmansk, under arrest.

After several days, they were released and returned to their ship on a personal pardon, delivered in a telegram, from then-Soviet President Mikhail Gorbachev. It was a time of great hope for change in the relations between Russia and the West and improvement of cooperation in the defense of the environment.

Dima, who now lives in Stockholm with his wife, Anitta, and three children, has continued to work for Greenpeace for more than two decades.

On Sept. 18, the Arctic Sunrise was in international waters and more than 500 meters from an oil platform belonging to the Russian oil giant Gazprom. Several Greenpeace dinghies approached the platform, and those aboard attempted to place on a platform wall a banner protesting oil drilling in the fragile Arctic.

Their attempt was peaceful but unsuccessful, and they returned to the Arctic Sunrise. Then Russian commandos attacked the ship. They fired warning shots, roped down from helicopters and forced the people on board to lie on the cold deck.

All were taken to a Murmansk city jail and accused of sea piracy, a charge that could have landed them in a labor camp for up to 15 years.

Legal specialists from all over the world quickly rejected the charge of piracy. Under both Russian and international law, an oil platform, which is stationary, cannot be pirated. In other words, an island in no way can be construed as a ship.

Piracy also requires premeditated action by the attackers to take another’s property for their own interests. It further must involve violence or the threat of violence.

On Wednesday, following a legal challenge from the Netherlands, Russia changed the charge to hooliganism, which can bring a maximum seven-year prison sentence. The charge requires the person either to have used an object as a weapon or to have a hate-related motivation — the Greenpeace group had neither — and to have resisted authorities. Greenpeace abides by the principle of non-resistance.

A year ago, Greenpeace activists made a similar peaceful protest, placing a banner on the same oil platform in plain view of the Russian Coast Guard. No one tried to stop them, and the action went almost unnoticed by the world press — indeed, the world — at that time.

Greenpeace is a well-recognized international organization that uses only peaceful means. Its principles are based on a tradition of nonviolent protest. Its members never use violence, although violence is often used against them.

Amnesty International, Human Rights Watch and 11 Nobel Peace Prize laureates and millions of people around the world have called for the release of the Arctic 30.

Dima and the others are threatened with long prison terms because they love and defend nature. That includes the Russian Arctic, which is threatened by senseless and dangerous drilling.

I know only too well what a prison term in Russia means. I was arrested for participating in 1968 in a demonstration against the Soviet invasion of Czechoslovakia. Lev Kopelev, Dima’s grandfather on his mother’s side, a Soviet writer, spent eight years in Soviet prison camps because he protested the looting and raping of the German population by Soviet officers and soldiers during World War II, when he fought the Nazi army.

Dima’s grandfather was arrested under Joseph Stalin, and I, Dima’s father, was arrested under Leonid Brezhnev. The Soviet Union doesn’t exist anymore, but Dima has been arrested under Russian President Vladimir Putin — a former member of the Soviet secret police, the KGB. Is it not the time to break the cycle?