You are not alone here, Kevin. I have had a couple of games now where my Democracy totally crashed. I usually make the mistake of wanting to stay in democracy, 'Just a couple of more turns - I'm so close to that tech.'
All to often, I realize that I should have made a switch to a government that handles war better.
It seems that prolonged wars are doom for a democracy. Of course, this is my own experience - many people on these boards swear by democratic wars. It seems that no matter how many luxuries I have (which is usually plenty, as lux brokering is a main strat in most, if not all, of my games), who it was that started the war, or where my entertainment slider is set, I never seem to be able to maintain wartime for very long.
I know that I play the government wrong. It seems that a democracy would be good for short, one front wars. I, though, start that short war, then get distracted by the next civ on the list. Too impatient to wait for the war to run its course, I start (or provoke) other ones with other civs.
I have been experimenting with a Republic in longer wars. Anything besides the terrible tech rates of a Monarchy and a (shudder) Communist state.