Final answer:
The most accurate term for someone who takes power of a country through illegitimate or controversial means is a usurper. While dictators maintain power by force, a usurper is specifically someone who takes power without a legitimate claim. Authoritarian governments often retain power through intimidation, undermining the legitimacy perceived by citizens.
Step-by-step explanation:
If someone were to take control of a country through illegitimate or controversial means, they could be called a usurper. A usurper seizes power typically without the legal right to do so, often overturning the existing order or regime. This contrasts with the term dictator, which denotes a ruler with absolute power, possibly gained initially through illegitimate means, but thereafter maintained by force, intimidation, and control. Though there is nuance and potential overlap in these terms, the word that best fits the description given is usurper.
The legitimacy of a government generally rests with the perception of its citizens, whether they feel it is legitimate and responsive to their needs. In many democratic societies, power is considered legitimate when it results from a vote of the people. By contrast, power maintained through coercion, and without popular consent, as practiced by some authoritarian governments, is seen as illegitimate. Elections themselves do not necessarily confer legitimacy, especially if they are not free and fair.