Expanding voting rights in America was necessary if the nation was to live up its own declarations about democracy and government.
The Declaration of Independence (1776) famously asserted: "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights," and "that to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed." It is true that the men who signed the Declaration of Independence had in mind only white males when saying "all men are created equal." But the underlying principle of their words applied to all humanity -- including non-white and non-male persons. For the government to derive its powers justly from the consent of the governed, Native Americans, African Americans, and women needed to be included as voters. And certainly adults considered old enough to fight and die for their country at age 18 deserved the democratic right to vote in their country too.
The Constitution of the United States (1789) famously began with the words, "We the People of the United States ...." For that phrase to ring true in a democracy, the right to vote needed to be granted to all adult citizens. Otherwise, we could not continue to claim to be what Abraham Lincoln described as a nation with "government of the people, by the people, for the people."
