All right out of Stalin’s playbook. First you arrest them, then you hold them indefinitely in jail without contact with the outside world. During this time you torture them until they confess to whatever made-up “crime” you accuse them of, and preferably falsely rat out others who the torturers want to give the same treatment to. Then you sentence them to decades of “hard labor” in a remote camp, and to more torture. Sentencing done by a non-judicial, non-accountable administrative tribunal whose primary job is producing “guilty” verdicts in order to meet their quotas.

Apply this method to the weakest first, and then to the working classes (including veterans) and then to the middle- and upper-classes (administrators and engineers and military leaders and especially “intellectuals”), rinse and repeat, until you’ve got yourself a society composed of individuals who live in utter terror of Uncle Elon and Tusk, and of being arrested themselves. Members of that society will never step out of line, will never be a threat to the regime.

Here’s a first-hand description of how it works : https://archive.org/details/TheGulagArchipelago-Threevolumes/The-Gulag-Archipelago__vol1__I-II__Solzhenitsyn/