"do you think it is a good idea for the president of the united states to have the authority to limit or shutdown internet traffic to and from any compromised federal government or u. s. critical infrastructure information system or network? why or why not? "

No, i do not think it's a good idea.
If the president could control the flow of information in the internet, He basically can promote only the sites that are suitable to his Agenda and demoting the ones that don't.
This situation is very similar to a Tyrannical Government that forced its people into only thinking a certain way.