Purge

For such a simple word, purge has quite a history.

Purge (v) - To cleanse or purify. From the Latin word purgare meaning to make pure.

Purge has been the word of choice for the periodic removal of the ideologically unclean from a political movement. In recent history:

• Ba'athist Purge in Iraq - Following the United States invasion of Iraq there was a effort to prevent anyone who had been a member of Saddam Hussein's Ba'ath Party from achieving any position of responsibility. That quickly became counterproductive as most of the Iraqis who knew how to accomplish anything had been members of the Party.
  
• Nazi Purge - On June 30, 1934, Hitler sent the SS out to rid him of bothersome members of his party. Called Reichsmordwoche in German, "Blood Purge" (literally "empire murder week"), it came to be known to the world as the Night of the Long Knives.
  

• Soviet Purge - The Soviet Union under Stalin loved their periodic purges. In 1927 Leon Trotsky, one of the founding Russian Communist revolutionaries, was expelled from the Communist Party along with his supporters, Trotskyites. But that was nothing next to the Great Purge of 1935-1938. Being purged from the Communist Party under Stalin then meant arrest, torture, and execution. They were even airbrushed out of pictures. Over a million Russians died as a consequence of the Party purges.
• RINO Purge - RINO - Republican In Name Only. Republican conservatives are in a lather to cleanse their party of the moral pollution of liberalism. The list of which Republicans need purging is fluid but it appears to be: 1) Any Republican east of the Hudson River; 2) John McCain; 3) Any Republican who voted with Democrats at least once in 2009. While the Republican Party purge has not yet risen to the level of demanding blood, that may change.