The Limits of Democracy

At what point does a democracy turn into “not a democracy”?

Heh heh, that question seems a bit silly.  It’s pretty easy to tell a “democracy” apart from something that’s not a democracy.  Valid voting systems, universal suffrage, etc.  However, even in a perfect democracy, there are inevitably groups whose opinions and desires are decided against.  There are segments of the population for whom the tax system is not representative of what they want.  There are segments of the population for whom social welfare programs are not representative of their desires.  So, does that mean those groups are being oppressed or exploited?

The glossary of terms at www.marxists.com has the following definition of “dictatorship”, and I think it’s effective as an anti-definition of democracy:

Dictatorship means the imposition of a rule on others who do not consent to it.

I think there are some interesting principles that are brought to light.  The existence of a democracy is fully contingent upon the population consenting to the governmental decisions being made.  It only exists when the people on the losing side of a vote say, “Ok.  It was a fair vote.  You won, and we will support that outcome.”  If the losing side of a vote says, “We don’t agree with the outcome of the vote, and we will not support it,” then democracy is not in existence.  Interestingly, the existence of democracy can only really be identified in retrospect.

Are there issues that are of such importance that anything but a consensus vote will effectively result in non-democracy?  Does that mean that such issues should generally not be things the government can mess with?