Only if
> the domination of the capitalist class _and_ of capitalism itself is
> threatened can it be said that "America" is in decline.
>
In decline relative to what? The fading power of America's national bourgeoisie as an actor on the global stage, as compared with other, rising national bourgeoisies (in the BRICs, etc.), is certainly a phenomenon worth noticing. If you choose not to call it "America's decline," that's your prerogative, but what term do you suggest instead?
-- "Hige sceal þe heardra, heorte þe cenre, mod sceal þe mare, þe ure mægen lytlað."