[Help-bash] Why won't set -v work?

[Bill Gradwohl]

I'm experimenting and came up with something I can't explain.

#!/bin/bash
declare parm='pass1'
#case "${parm}" in 
#   'pass1')
      set -v
      if true; then echo True; fi
#    ;;
#   *)
#   echo Hello
#   ;;
#esac

When executed, the above works as expected. 

If you remove the octothorpes to activate the case statement and run it again, the set -v appears non functional. 

Why?

Thank You

-- 
Bill Gradwohl