That's right! Al Gore invented the internet, let's all go kick his ass!
I got your inconvenient truth right here, motherf*&¨%!
The Avengers have a pretty sweet deal.
They're essentially calling their own shots, and getting paid by uncle sam for doing what they were previously doing for free. It's a nice win win, as it helps the Avengers out and keeps the government out of the "completely useless" category.
I'm not sure the government has given Steve a single actual "order" since getting his job. I think the goverment at least has been smart enough to realize that the best possible thing they can do is literally stand out of the heroes way and let them do what they need to do. And if they actually wanna help out in the process, even better.
To my understanding basically Steve Rogers has been put in charge of super powered affairs and was technically the equivalent of director of Shield.
The president put him in power and can easily remove Steve from the position as he did with Osborn.
So in that regard they are certainly the "Sanctioned authority".
Its worth noting that the government mostly lets Commander Rogers handle everything as he sees fit, and Rogers himself allows certain groups under his watch to do their own thing, like SWORD or the set up for Cages Avengers. Theres vey little micro managing and a lot of trust between parties, which is probably the reason Steve was placed there to begin with.
Hell sometimes Steve is able to pull rank with super security.
So he's given power by the government, but is not exactly "working" for them, if you mean that they do what the executive or legislative branch want to do with their every step. He's not a puppet or an arm of the US is what I mean, he's the man they trust to make the decisions over super crime and the like.
Its mostly on Steve to do as he sees fit, the government just allows him to do it and can stop him if need be.Sanctioned really is the best word to describe the Avengers.
Steve Rogers: You ready to follow Captain America into the jaws of death?
James Barnes: Hell, no! The little guy from Brooklyn who was too dumb not to run away from a fight. I'm following him."
of course it isn't. shield didn't even know about sword until abigail wanted them to. that's how far they are over steve's pay grade.