Citizens voting.
Citizens voting.

The U.S. Constitution specifies how the government is run and how power is distributed. It also specifies what rights and privileges citizens have, which includes -- but is not limited to -- voting rights. Six amendments to the Constitution deal with voting, and they all reflect the era in which they were passed.

Presidential Elections

The 12th Amendment, ratified in 1804, specifies how the president and vice president are elected. Rather than be elected by popular vote, the nation's top officials are chosen by the electoral college, a group of electors from each state equal to the number of its senators and congressmen. This amendment makes it possible to win a presidential election without winning the popular vote.

Race and Voting

The 15th amendment, ratified in 1870, made voting available to all men over the age of 21. It explicitly states that people cannot be barred from voting on account of their race. This reflects the post-Civil War sentiment and the fact that African-Americans were -- gradually -- becoming more integrated into American society.

Senate Elections

The 17th amendment, ratified in 1913, changed how senators are elected. Before 1913, each state's legislature elected senators. The 17th amendment lets senators be elected by popular vote, a process that remains to this day.

Women's Suffrage

The 19th amendment, ratified in 1920, gave women the right to vote. Before this, women were prohibited from voting in federal elections.

Poll Tax

The 24th amendment, ratified in 1964, abolished poll taxes for federal elections. Before this, black people often were excluded from elections because they did not have the money for the poll tax, which disenfranchised them. The 24th amendment eliminated what was essentially a means-based election system.

Voting Age

The 26th amendment, ratified in 1971, lowered the voting age to 18 from 21.