You don’t need to argue about if what happened in Egypt could happen in the US. It could. The President has had an Internet “Kill Switch” since before there was an Internet. The Communications Act of 1934 includes a provision in section 706, that makes that pretty clear:
“Upon proclamation by the President that there exists war or a threat of war, or a state of public peril or disaster or other national emergency, or in order to preserve the neutrality of the United States, the President, if he deems it necessary in the interest of national security or defense, may suspend or amend, for such time as he may see fit, the rules and regulations applicable to any or all stations or devices capable of emitting electromagnetic radiations within the jurisdiction of the United States”
In 1996 the Communications Act was amended to grant the power to limit communication between entities giving the President the power to effectively turn off just Twitter, and Facebook, or communication to a specific country.
This isn’t limited to the Internet. The President actually has the power to turn off TV, Radio, and Phones if it is deemed necessary for the safety of the country.
It should be remembered that if the President declares a state of emergency the communication on the Internet may be the least of our worries. Just as some civil liberties were suspended after 9/11, if the US Government wants to the President can suspend Habeas Corpus, freedom of speech, right to gather, and a lot of other things in the name of national defense.
Our bigger concern should be the duration, and the conditions under which such restrictions on our rights and liberties such acts can be taken. I don’t intend to minimalize the tragedy of 9/11, but honestly it was not likely that we were going to see more attacks on US soil, and it certainly wasn’t going to result in the overthrow of the Government, which is what these acts are designed to prevent.
In 1934 the intent was to be able to prevent national broadcasts of overthrown stations, or broad communication of national secrets. Not to prevent individual communications between people. Turning off the Internet is a much broader disruption of speech, than turning off TV, since individuals can report a story on the Internet, and few of us use TV as a mass media to broadcast things happening on our block, or to spread our personal message of peace, hate, support or rebellion.