At these moments, America has carried on not simply because of the skill or vision of those in high office, but because We the People have remained faithful to the ideals of our forbearers, and true to our founding documents.
[see grammatical analysis here.]
David Rose wrote to sys-func and Sysfling on 18 March 2015 at 09:15, analysing the above clause complex from Barack Obama's Inauguration Speech:
Now from discourse semantics…
‘America’ and ‘We the People’ are modally responsible
 The notion of the Subject as the modally responsible element is from the grammar, not discourse semantics. Halliday & Matthiessen (2004: 59):
A clause has meaning as an exchange, a transaction between speaker and listener; the Subject is the warranty of the exchange. It is the element the speaker makes responsible for the validity of what he is saying.
Halliday & Matthiessen (2004: 194):
Thus while a Goal readily becomes Subject … it is unusual to make a Scope element ‘modally responsible’ in this way …