As the Constitution of the United States was being written, a lady asked Benjamin Franklin what he and the other writers were creating. He replied, "A republic, madam-- if you can keep it." Generations later, Abraham Lincoln also posed it as a question whether "government of the people, by the people and for the people" is one that "can long endure."
Just as there are nations who have not yet developed the preconditions for freedom and democracy, so there are some people within a nation who have not. The advance toward universal suffrage took place slowly and in stages.
Too many people, looking back today, see that as just being biased against some people.
But putting the fate of a nation in the hands of the illiterate masses of the past, many with no conception of the complexities of government, might have meant risking the same fate of "one man, one vote-- one time."
Today, we take universal literacy for granted. But literacy has not been universal, across all segments of the American population during all of the 20th century. Illiteracy was the norm in Albania as recently as the 1920s and in India in the second half of the 20th century.
Bare literacy is just one of the things needed to make democracy viable. Without a sense of responsible citizenship, voters can elect leaders who are not merely incompetent or corrupt, but even leaders with contempt for the Constitutional limitations on government power that preserve the people's freedom.
We already have such a leader in the White House-- and a succession of such leaders may demonstrate that the viability of freedom and democracy can by no means be taken for granted here.