"No offering group or individual health insurance coverage shall be required to participate in any Federal health insurance program created under this Act..."

But it does not read correctly if the parenthesis are taken out. Parenthesis clarify a statement and are independent of the words of the rest of the sentence; therefore, when you take out the parenthesis and the words between them, the sentence should still be able to be read and be grammatically correct.

This is what I remember, never made lower than a 90 in English classes. Perhaps someone else can chime in?