Not a bad body of posts to read through. I won't try to get into the whole left/right debate, but would like to offer this quote from the preamble of the Declaration of Independence.

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights,[71] that among these are Life, Liberty and the pursuit of Happiness. That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness.
I think that the third line, beginning "That whenever any for of government....etc." is the one point most apt to the thread. It answers entirely, for myself in any case, the question of whether it would be better to retain a democracy or adopt a government that seems "right" to the governed. It means that if the people feel that adopting a different government, notice that no distinction as to democratic or not is made, seems preferable to them, than it is their right.

PS: I appreciate all the references to Cromwell, a fascinating historical figure to say the least.