He wanted to kill King James. Regicide is always based.

I know you’re being cute but “soviet” is indeed a word in English: http://dict.org/bin/Dict

  Soviet
      adj 1: of or relating to or characteristic of the former Soviet
             Union or its people; "Soviet leaders"
      n 1: an elected governmental council in a communist country
           (especially one that is a member of the Union of Soviet
           Socialist Republics)

And it means what I intended it to mean, the official state ideology of the USSR: https://en.wikipedia.org/wiki/Ideology_of_the_Communist_Party_of_the_Soviet_Union

There is overlap especially when you don’t confuse communism as the broader framework with state communism or even worse soviet communism.