To be totally realistic and again, this is based as much if not more on the previous run than this one the U.S. would be hardpressed to invade Wakanda. Now to be honest, Wakanda came off as a bunch of punks in the early arc as far as I'm concerned. These guys turned back invading white imperialists without coming outside of thier houses in the first issue, but 5 second rate supervillians took them to the woodshed. I mean, they repelled them but their invasion plan was so BASIC I'm shocked that they got as far as this did in Wakanda.
In the previous run they talked about how T'Challa hid a whole battle cruiser in the Hudson river without the U.S. government even knowing it was there. THAT's why the Wakandan's are bad new for the U.S. It's not an issue of the U.S. 'winning' of course inevitably the U.S. would WIN, more people, money troops etc. but Wakanda would make it so damn bloody, expensive and difficult to wage the war that the U.S. would probably back down into negotiations after a few months because Wakanda wouldn't fall. Then again, I'm going off the previous series, I can't even really tell how tough this Wakanda is. Everybody SAYS they're so tough, I don't really see it. When Batroc the Leaper a SEVERLY depowered Klaw and some nerd on Luno-the-flying horse can cripple your defenses I have my questions.