At the height of the Ottoman Empire the method of succession was that as soon as the old Sultan died the eldest son of the chief concubine had all his half brothers killed so they could never be threats to his rule. England had a slightly more indirect process – the Wars of the Roses, for example, went on until there was only one possible king left, and there were numerous other battles, invasions, murders. In most countries indeed, at various times, potential kings battled it out with each other until the rivals were dead. And many of their subjects, especially if they had picked the wrong side. Same true for some countries after disposing of kings and becoming republics, notably Revolutionary France and the Soviet Union – jails full and bodies disposed of.
You could easily argue that while the emergence of democracies was a means of letting first the rich, then ordinary citizens, and finally women, vote to choose their leaders, an even more important advance of a democracy was in establishing a permanent structure of government which included a legal opposition (“His Majesty’s loyal opposition” in England to make it really official), an alternative government. Well and good, until some of the leaders elected by the people began to think that they should rule, in the interests of the people of course, forever, and in that circumstance having an opposition, an “alternative government” was not only unnecessary but might confuse the voters.

So in parts of the world governments began killing, jailing, demonising, silencing, opposition parties and leaders. Originally in countries including Germany, Chile, Argentina, Soviet Union, Indonesia, China. More recently in countries such as Malaysia, Russia, Zimbabwe, Iraq, Iran, Pakistan, Ukraine, Burma. Not democracies – a democracy could be defined as one which has free and fearless opposition parties, alternative governments in both name and reality.
This sort of thing didn’t happen in western democracies of course, including our own (although the aftermath of the Qld election is worrying). Governments didn’t like oppositions, but generally treated them according to the old adage “be nice to people on your way up because you will meet them again on your way down”. But more recently in America, quickly followed by here, the opposition parties decided they would turn the tables. Allowing for different systems, Republicans and Liberals have blocked as much govt legislation as possible, blocked appointments, attacked public servants, put gunsights on pictures of opponents, called for killing, tried to delegitimise the leaders of the governments, set up fake protest groups, screamed abuse and disrupted parliamentary proceedings, and, recently here, have tried to destroy the careers of the Speaker of the House, and one of the MPs, in order to bring down the government.
Same approach, in reverse, as from those dictatorships. Just as damaging to a democracy.