"One person, one vote" is a guiding principle of American democracy. But its exact meaning continues to be debated.

　　The U.S. Supreme Court recently decided one dispute.

　　In April, the court ruled that states can count all residents to set up election districts and not just those allowed to vote.

　　The issue is important because it decides how many seats in Congress and legislatures are given states and local communities.

　　Supreme Court Justice Ruth Bader Ginsburg wrote the decision. In her ruling, she provided a history lesson.

　　In 1776, when the U.S. declared independence from Great Britain, only people who owned property could vote. It was not until 1920 that women won the right to vote.

　　Slaves were not permitted to vote. It took the Voting Rights Act of 1964 to end rules that stopped African-Americans from voting in some southern states.

　　In 2016, children under 18 still cannot vote. Nor can prisoners.

　　But in her ruling, Ginsburg wrote the nation's founders believed everyone --- whether they voted or not – should be represented by their government. She said all people need government services.

　　"Representatives serve all residents, not just those eligible to vote," Ginsburg wrote.

　　Michael Li works on voting rights issues for the Brennan Center for Democracy in New York. He said the Supreme Court ruling is important.

　　"We fought a revolution over taxation without representation and early on in our history we decided that people should be represented the same way, whether they vote or can't vote," Li said.

　　He said the Supreme Court ruling will help undocumented immigrants because they will continue to get counted, even if they cannot vote.

　　Two Supreme Court Justices – Clarence Thomas and Samuel Alito -- also voted with Ginsburg in the 8-0 ruling. But they said the ruling should have limited effects.

　　Thomas and Alito said the ruling means the states can draw election districts based on all residents -- not just voters. The ruling does not mean the states must do this.

　　"The Constitution leaves the choice to the people alone – not to this court," Thomas wrote.

　　Currently, all 50 states use U.S. Census Bureau data to determine representation. That includes all those counted – both voters and non-voters.

　　History of "one person, one vote"

　　American history is full of fights about how to define "one person, one vote."

　　In 1787, there was a dispute between the northern states, where slavery was illegal, and southern states, where slavery was permitted.

　　In the North, people argued states that deny African-Americans the right to vote – and all other freedoms – should not count them for representation in Congress.

　　As a compromise, a slave was counted as 3/5 of a person. With the end of slavery in 1865 after the Civil War, the rule ended.

　　In 1964, the Supreme Court ruled that states must create legislative districts based on equal representation. At the time, some big cities, such as Los Angeles, were given the same representation in state legislatures as small communities.

　　There are other voting issues that likely will make their way through the courts. One is whether requiring voters to show picture identification violates the Constitution's equal protection guarantee.

　　Supporters say requiring identification reduces fraud. But opponents say fraud is not a problem. They say the requirement will make it hard for minorities and older people without identification to vote.

　　Therefore, these opponents say, requiring picture identification violates the principle of "one person, one vote."

　　I'm Bruce Alpert.

　　Bruce Alpert reported on this story for VOA Learning English. Hai Do was the editor.

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