Although it's not specifically stated as a right in the US
Constitution, the right to travel freely in your own country (without
"papers"), is generally believed to be a fundamental right. The right
to travel freely is also a benchmark for a measure of freedom in all
countries. Both Nazi Germany and the Communist system required
"papers" to travel from one city to the next. I dread the day when I
land at the airport, and a uniformed officer comes up to me and says,
"papers please". It will be a major loss of a fundamental right.

Now, things ARE different in war. But we can't have "continual" war,
as the "war on terrorism" or the "cold war". I can accept temporary
restrictions during a crisis (gasoline rationing in WWII, sugar
rationing, restricted travel, blackout curtains along the east coast
etc), but not permanent or semi-permanent ones. If we are in a cold
war, sorry, we HAVE to go back to having our fundamental rights and
take some risk of a terrorist attack, which, by the way, there is no
way of preventing with complete certainty.

There has been one terroist attack on the US. And it was terrible.
4000 people lost there lives. But there are over 60,000 deaths due to
car accidents a year. Just how much freedom are you willing to give
up?

The "homeland sucurity" advocates make the argument, "but yes, we
could have a nuclear attack, wouldn't you give up your freedom to
travel for preventing such attack?" BUT their security measures don't
make such a guarantee. With the draconian travel restrictions we give
up our freedom to travel and STILL are under a threat of attack.

There are things they can do. Baggage matching, baggage scanning,
linking visa data with Social Security data etc, to keep tabs on
visitors to our country. Most of these actions limit our freedom to
travel very little. So do those things. But don't start asking me for
"papers please". We can't go there.