• This is also a victory for President Trump's Justice Department, which has sided with the administration's support for voter eligibility restrictions that it claims will crack down on alleged voter fraud.

The details: All states periodically clean up their voter rolls, but only a handful remove voters simply because they’re inactive. In Ohio, a presidential swing state where the practice could have an even greater impact, the practice is said to be more aggressive than any other.

• How the system works: Ohio sends notices to registered voters who fail to vote in a two-year period. If they fail to respond and do not vote in the next four years, their names are removed from the rolls.

A 2016 Reuters analysis of voter lists found that in the state’s three largest counties — Cuyahoga (Cleveland), Hamilton (Cincinnati) and Franklin (Columbus) — voters have been kicked off the rolls in Democratic-leaning neighborhoods “at roughly twice the rate as in Republican neighborhoods.”

• That's because Republicans are more likely to vote in both congressional elections and presidential contests.
• It also found that neighborhoods with a high proportion of poor, black residents are hit hardest. Both Republican and Democratic officials in Ohio have purged inactive voters over the past 20 years.

In a thundering dissent, Justice Sonia Sotomayor said the conservative majority ruling "entirely ignores the history of voter suppression against which the [National Voting Rights Act] was enacted and upholds a program that appears to further the very disenfranchisement of minority and low-income voters that Congress set out to eradicate."