it was started by the British in the 1880's
The French Revolutionary ideas of nationalism and democracy did not only spread throughout Europe, but to France’s colonies as well. The new idea of making the silenced voices heard sparked a new idea in Haiti- independence. The Haitians wanted to do what the Third Estate did, make their voices heard.
Even if the country is in distress, the people should still have their rights. Like when the japanese were forced into internment camps, that was bad. They lost all their rights. Some people might say that we shouldn't do this since we sometimes need to take rights from some people just because of something that happened from where they were.
C: The allies were near defeat
No, states do not have the power to change the voting age.