It's time we added the first 21st Century amendment to the Constitution -- an amendment that parallels the First Amendment but explicitly prohibits the government from ever shutting down the Internet. Freedom of the Internet in today's world is just as important as freedom of the press, religion or speech.

As revolutions spread around the world questioning dictator after dictator, it is clear that the Internet has been the same kind of catalyst that a free press has been in past democratic revolutions -- it has given people an easy way to share their experiences, a tool for organizing, and served to publish atrocities in cases where the press was blocked.

Dictators and governments around the world are busy studying this phenomenon, trying to understand how they can control it. Governments refuse to give Blackberry contracts unless they have the ability to snoop on its traffic. Even in the U.S. the Internet has to be available for government monitoring and supervision -- justified quite fairly on the basis of the need to catch criminals and terrorists who use the Internet as they used the phone system in the past.

And the Secretary of State Hillary Clinton has given a series of speeches on Internet freedom. She has said clearly that other countries should refrain from cutting off access to the Internet and social networks when besieged by protesters, noting that "those who clamp down on Internet freedom may be able to hold back the full expression of their people's yearnings for a while, but not forever."

But what if we were facing some significant discontent in the U.S. today or in the future? Imagine if anti-Vietnam protesters had the internet as a tool then and their marches had doubled and tripled in size -- would the U.S. have considered curbs on the internet? Imagine if during 9/11 the government became convinced of a wider operation and conspiracy in play. Would President Bush have considered shutting down the Internet? Would those presidents have pushed such a button if they had it? And what would have prevented them from doing it -- a constitutional amendment from 1789?

Right now all of our broadcast media are supposed to react to encoded government messages to play them to the exclusion of anything else in the event of an emergency. This is the successor to the Emergency Broadcast System I grew up with, listening to the endless sound of "just a test." It has been a given that there is nothing in the Constitution that would prevent the U.S. government from commandeering all communications in whatever they deemed an emergency. That emergency could be a threat from the outside or within.

So the question is whether we are prepared, as we tell others to keep their hands off the Internet, to live our values with an ironclad constitutional amendment committing to do the same. I'm not talking about an amendment that would weigh into the complex economic questions of net neutrality and tiers of Internet speed. Those are commercial issues that will surely be settled appropriately over time.

I mean the kind of amendment that would make it illegal for a state legislature, Congress, the president or the military to shut down or otherwise restrict access to the Internet for political or so-called national security reasons. You can see it developing in the future -- fear of attack -- shut it down. Out of control demonstrations, shut it down. You see it in country after country now, and always we think it could never happen here. And yet we did inter the Japanese, the CIA has had a string of abuses over the years, and Nixon did use the FBI and other government agencies for his own benefit -- and these things happened in the last 40 years.

In such national security questions, there are always difficult cases like the "ticking time bomb" scenario where it seems to make perfect sense to use extreme measures. And there could always be a cyber-attack that requires some action to prevent the spread of a virus that could destroy millions of computers or take over our power grid.

But despite these hard cases, it is time for the U.S. to take the lead with a model constitutional amendment on preserving and defending internet freedom. The First Amendment has withstood the test of time, but it does not explicitly cover social networking or the Internet any more than it covers shut downs of the phone system or TV broadcasting. And especially as agencies like the FBI and NSA are pushing to further their Internet oversight through stricter data retention laws and a more-efficient online wiretap system, it makes no sense to leave these things to chance.

Such amendments are rarely about today and their impact here and now -- they are about an unexpected situation and an unexpected president bending the law to the maximum to preserve their own power. Anything as powerful as the Internet is something that governments irresistibly will try to control over time -- they are at the heart of our communications here and abroad. We have urged others to say hands off -- how about committing the US to the same position for the next 200 years in the only ironclad way we have -- a 21st Century Constitutional Amendment on Freedom of the Internet.