For these crimes we need to bring back public execution once the verdict of treason has been rendered. Methods can be discussed.
And, if we do that, I think the manner of execution needs to be the most dramatic, maybe bloody--e.g. firing squad. If we do it for education of those tempted to misbehave--then make the lesson the most vivid possible.
However, we do well to have very stiff criteria for those so sentenced. IIRC, Moses' law required 3 witnesses catching the offender IN THE ACT.
We know that given the evils in human nature, such a practice could easily be turned to evil ends.