America is not an empire, but an idea. The 'empire in decline' is a trivial concept. One thing America will continue to do is to transform and recreate itself - and the world. It doesn't know any other way. Its superiority lies in its flexibility and openness. It will keep thriving even as a non empire - just because ot the abysmal lack of creativity of most of its contemporaries, who lack that strong (and pragmatic) foothold in... the future.
U.S., allies conduct 20 air strikes in Syria and Iraq against ISIS, says U.S. military (Reuters)
from the article: WikiLeaks cables tell the story of an empire in decline