There is valid concern over an 'internet' takeover. It always starts with seemingly small steps ICANN's role and when you least expect it the 'politics' rolls in explaining away very legitimate concerns.
Please view this video by Senator Cruz on YouTube to get a better understanding Sen. Cruz Urges Colleagues to Stop Obama's Internet Giveaway
and please review H.R. 1212 Internet Freedom Act
It is not so much that they won't try to do it. I am speaking of it from a purely technological aspect. With the way networking is setup now they CANNOT shut it down for long. They could disrupt it but people like me could immediately start working on our network equipment and restore it bit by bit. SO law or no law there are technological limitations they cannot overcome. Another thing about modern day law makers, most of them don't really grasp how this technology works.