You are too pessimistic.

> historical precedent.

There's plenty of historical precedent
where the US democracy worked. E.g.,
we passed prohibition -- 2/3rds of
the House, 2/3rds of the Senate, and
3/4ths of the states. When we saw
how dumb it was, we repealed it.

Recently SOPA and PIPA were close to
passing. A lot of people in the
tech community raised hell, and
the bills went down in flames.

Sure, the Constitution doesn't
solve all the problems. Instead,
as Jefferson said,

"The price of liberty is eternal
vigilance."

So, to make the Constitution work,
citizens have to keep pushing.
You mentioned threats, and there
are threats, but they can be defeated.

Once public opinion polls rise
significantly over 50%, politicians
start to pay close attention.

The main issue, then, is just what
the voters want. Sure, the MSM,
political ad campaigns, lying
politicians, etc. can have
big effects, but in the end
the voters know a lot about
lying, duplicity, manipulation,
etc. I believe that the Internet
will be helping -- it seems to
have helped a lot with SOPA and
PIPA and to have gotten the
Snowden efforts front and center.
No doubt some cases are on the
way to the Supreme Court --
from Google, EFF, ACLU, etc.
I doubt that the Patriot Act
will come out whole.

Indeed, I believe that YouTube
is helping a lot: Once a politician
gives a speech, then due to YouTube
the politician can't assume that
the voters will easily forget.
And for text data on politics, the
Google/Bing keywork/phrase search
engines are terrific.

Look at the US efforts in Viet Nam:
Before WWII, Viet Nam was a
colony of France. Ho Chi Minh
was a dishwasher in Paris!

During WWII, Japan made Viet Nam
a colony. The US worked with
the Viet Namese 'nationalists',
e.g., to rescue downed US
pilots.

After WWII, the French got
one of the peace conferences to
let them back into Viet Nam,
and war broke out.

Then the US had just fought against
the Axis of Germany, Italy, and
Japan, and it looked like there
was another axis on the way with
Moscow, Peking, and Hanoi.
So, the US helped France in
Viet Nam. The French lost.

By then the US had been fighting
in Korea: The North was backed
by Moscow and Peking and wanted
the whole country. The US and
parts of the UN wanted to
'block' that effort. So,
there was the war in Korea,
really, still simmering.

So, when the French lost in
Viet Nam, the US wanted
to divide the country
and have the southern half
allied with the US.

Alas, whatever the Ho government
was, it was able to maintain
power. And the US couldn't
find a government to back
in Saigon that could maintain
power -- a Saigon politician
did not dare sleep in a
small village in the South.

So, the US kept backing
governments in Saigon
that kept losing.

In the US, the foreign policy
'wise men', Keenan, Dulles,
Rusk, Bundy, etc. kept screaming
that the US had to stop Hanoi
or "dominoes" would fall all
across the Pacific and land
in California or some such.
LBJ and Nixon really bought
into this stuff, big time.

So the US bent itself all out of
shape, inflated its economy,
lost the lives of 50,000+
US soldiers, etc. trying to
prop up loser governments in
Saigon.

Why? Because no US politician
wanted to see Hanoi take Saigon
and, then, suffer the charges
that they "lost Viet Nam" and
were "soft on the atheistic, international
Communist conspiracy about to
take over the world and
march into Washington, DC".
That sales pitch worked really
well in the US from the end of
WWII until the US finally
was run out of Viet Nam with
people hanging off the
parts of US helicopters
whenever it was in the 1970s.

In all of this, it was really sad
that Ho worked so hard to
go to Moscow and Peking and, there,
poke the US.

Actually, in the end, Hanoi
and the US really had no serious
differences at all. Indeed,
now the US couldn't be happier
with Hanoi. The US could have
been happy with Ho and Hanoi
at any time from WWII until
the US totally lost.

But for your point about US
democracy, what finally got the
US out of Viet Nam was
the US voters, e.g.,
many thousands of them
marching on DC. Finally they
made such a big noise that
even President Ford gave only
half-hearted support for staying
in Saigon, and we left.

The US voters long bought into
that Rusk, etc. "domino"
theory. Eventually nearly
every young person knew
someone in their high school
days who had died in Viet Nam.
The predictions of the hawks
never came true. It was clear
that somehow the US just did not
know how to build a government
in Saigon.

It took US voters a very long
time, decades, to see these points.
But, eventually the voters saw,
and then the US was out'a there.

The bottleneck was the US voters
voting for LBJ and Nixon
instead of, say, McGovern.
I voted for McGovern;
he wanted out as in 'leave
now' which is eventually just
what we did and what brought us to
the present which is just fine.
But McGovern lost, badly.

There were lots of people saying
that we should get the heck out
of Viet Nam. One book went
"Are not winning, cannot win,
should not wish to win". My
view is that we burned enough
oil, say, in B-52s from Guam,
to enable OPEC.

We blew it.

Then, Afghanistan -- same song,
second verse. There, still,
no US politician wants to say,
"Leave. Now.". Me? I'd
have bombed enough of Akrapistan
to teach them a lesson and then
left, without ever setting a
foot on the ground.

The US needs to wise up.