ANY power in society must be considered legitimate to be recognized as such and thus function - voting is but one mechanism of such recognition. Every form of power, from hereditary monarch to democracy needs to be recognized as a legitimate authority to be able to function. It follows that withholding the recognition of legitimacy by the people will eventually lead to the demise of any power that be. It furthermore follows that if someone stays in power, he does so because his authority is recognized by a sufficient number of people.
Btw, autocracy in one form or another is by far the most widely spread form of government. Liberal democracy was a fluke that emerged from the struggles of the nascent European bourgeoise against the crown and aristocracy, and sustained itself as an alternative as the victorious bourgeoisie was coping with the threat of communism. But at this point of history, its usefulness has expired, as it threatens the ruling business class - so it will likely be curtailed. Sadly, most people would not mind that all as long as the descent to autocracy will be portrayed to them as restoring firm moral principles, eliminating deviance and debauchery, and making things run like a clockwork again. People like autocracy as long as they have someone "below" them to kick.
Wojtek