The U.S. Supreme Court on Monday unanimously upheld Texas’ method of outlining voting districts, rejecting a conservative argument that could have shifted significant voting power to predominately white, rural areas.

The court found in Evenwell v. Abbott (pdf) that Texas did not violate the long-established “one person, one vote” doctrine in carving out its voter maps. The conservative activists who brought the case argued that the state should only consider eligible voters, rather than total populations—an argument the court rejected.

Monday’s decision allows, but does not require, all states to count every resident when mapping out legislative districts after each census.

Legislators “serve all residents, not just those eligible or registered to vote,” Justice Ruth Bader Ginsburg wrote for the majority. Non-voters, including children, “have an important stake in many policy debates,” like education.

Democracy advocates lauded the ruling.

“Today’s decision affirms one of our most fundamental values as Americans: that every person counts,” said Common Cause president Miles Rappaport. “Our nation’s charter begins with the words ‘We the People;’ that means everyone—not just those who vote—is entitled to equal representation at every level of government.”