You know that 主義 is "-ism." Add that ism to people who want to protect and conserve their country so it stays just the way it is (forever). That's conservatism and they're conservative people.
This word uses the reading of 保守的 for the first half and then the regular kanji readings for the second half. Combine those things and you'll be a master of righteousness and / or kanji.
My parents are both teachers and extremely old-fashioned conservatives.