In 1968 together with some other scientists he signed the so-called "letter of 46" which was a petition against the political trial of Yu. Galanskov, A. Ginzburg, A. Dobrovolsky and V. Lashkova.
Yuri Gagarin | Yuri Bashmet | Yuri Milner | Yuri Orlov | Yuri Andropov | Yuri Shevchuk | Yuri Baturin | Yuri Rozum | Yuri Gurevich | Yuri Averbakh | Yuri Trutnev | Yuri Stern | Yuri Shatunov | Yuri Semin | Yuri Nikulin | Yuri Landman | Yuri Kara | Yuri I. Manin | Yuri Galanskov | Yuri Ebihara | Yuri Dmitrievich Petukhov | Yuri Bogatyryov | Yuri Arbachakov | Yuri Ahronovitch | Yuri Zhirkov | Yuri Zavadsky | Yuri Yunakov | Yuri Yakovich | Yuri Vladimirovich Nesterenko | Yuri Vasilyevich Gulyayev |
During this time he established contact with dissidents such as Vladimir Osipov and the editors and contributors of the dissident magazine Sintaksis Alexander Ginzburg, Natalya Gorbanevskaya and Yuri Galanskov.