“Putin unleashed so many nationalist forces after Crimea he needs to be careful,” said Alexander Gabuev, an Asia expert at the Moscow Carnegie Center. “His hands are really bound by nationalist sentiment and the fact that his ratings are going down,” he added.
The Kremlin has responded to criticism from extreme nationalists with a mix of repression, jailing their most vocal and disruptive leaders, and tacit support.
The police on Tuesday arrested several protesters who gathered outside the Japanese embassy to protest any return of the islands. But the Russian authorities, who usually crack down hard on opponents of Mr. Putin, allowed a demonstration in central Moscow on Sunday by hundreds of nationalists and far-left activists united in hostility to any deal with Japan and also to Mr. Putin, whom they view as insufficiently robust in his defense of Russian interests.
Among those speaking at the protest rally was Igor Girkin, a former military intelligence officer who helped ignite the Russian-backed separatist rebellion in eastern Ukraine in 2014. Now back in Russia, Mr. Girkin, also known Igor Strelkov, commands a small but noisy following of self-declared patriots committed to expanding Russian territory and resisting, by force if necessary, any accommodation with the outside world.
“I will say just one thing. If the authorities decide, against the will of the overwhelming majority of the people, hand over to the Japanese two, one, even a piece of the Kurile Islands, we will not stop at any action, lawful or unlawful,” he told flag-waving protesters. A group of demonstrators from the Left Front, whose flag features a hand grenade, held up a large banner declaring Hokkaido, an integral part of Japanese territory, a “Russian island.”
As chants of “resign, resign” rose from the square, another group of protesters waved printed signed reading: “We will give away Putin instead of the Kuriles!”
The Soviet Union seized the Kurile Islands, some of which lie just a few miles from Hokkaido, Japan’s northern prefecture, in August 1945 and, after expelling Japanese residents, incorporated the remote, mostly barren islands into Russia’s Sakhalin region. Moscow and Tokyo agreed in 1956 to put an end to their wartime hostility and that two small parts of the territory — Habomai and Shikotan — near Hokkaido would be handed back to Japan after the signing of a formal peace treaty.