Answer
Rakovsky's arrest and imprisonment during the Moscow Trials were primarily attributed to his unwavering adherence to Trotskyist political ideologies. These beliefs, which diverged significantly from the dominant Stalinist line, made him a prime target for persecution during the height of Stalin's purges. Rakovsky's unwavering loyalty to Trotskyism placed him in direct conflict with the prevailing political orthodoxy, ultimately leading to his downfall.