The "Enemy Within" motif is two descending intervals, a perfect fourth and a diminished fourth, then back up ... The "Enterprise Incident" Romulan-ship motif is a symmetrical one, a falling half-step and a rising half-step: G-F#-F#-G.
Ok, so note 3 is below note 2 in Enemy Within, and notes 2&3 are the same in Enterprise Incident. I couldn't decide – with the one stuck in my head, I was having trouble hearing the third note clearly in the other.
They really don't have anything in common beyond having four notes and ending on the same note they start with, and sometimes having the same staccato rhythm
That's a funny comment. "They don't have anything in common except ____ and ____ and sometimes ____." Pretty darn similar. I would have said they are two 4-note themes differing only in the third note. (If you're right about the interval values, the second note is only a half-step apart between the two; and it would be easy to mistake them, transcribing by ear.) And having the same rhythm.
But different, as you say. Thanks for the info!
Has any of this music been published, as sheet music? I Googled some last week, when I last asked the question, but all I could find with a quick search was the main title music.