Does democracy necessarily lead to the'tyranny of the majority' and do you think global democracy is possible?

We have some specific limits in the American system that
try to prevent such a tyranny of the majority from taking place.  Take for
example:

1) The Filibuster -
you'll notice how difficult it has been for Democrats in the Senate, even with 59 seats,
to overcome Republican filibusters and take measures to a floor vote.  Even with huge
majorities it took 14 months and some procedural maneuvering to pass health care
reform.  It wasn't meant to be used this way, but it does give the minority party some
power.

2)  Individual protections and
limitations on power in the Constitution - The Bill of Rights trumps all
government actions by the majority that ends up being tyranny over minority viewpoints
and identities.  The limits on power in the Constitution are absolute, and prevent one
branch, say the Congress with most of government in it, from taking more
control.

3)  Independent
judiciary - Federal judges are appointed for life, and answer only to the
law and higher courts, not to the popular will of the
majority.

Limited global democracy, in the form of the
United Nations, is possible, but it is also pretty dysfunctional, and on a larger
governmental scale simply doesn't work with 6.5 billion people.