Washington (CNN) All four liberals on the Supreme Court dissented in Monday's 5-4 case upholding Ohio's method of removing voters from its rolls.

Justice Stephen Breyer led the charge, interpreting the National Voter Registration Act, also known as the motor voter law, as barring Ohio's process. Justices Ruth Bader Ginsburg, Elena Kagan and Sonia Sotomayor joined the dissent in full.

But then, on her own, Sotomayor went further and focused on something else: the impact the ruling will have on minority voters.

"Our democracy rests on the ability of all individuals, regardless of race, income or status, to exercise their right to vote," she wrote in a separate five-page dissent.

Her opinion earned a rebuke from conservative Justice Samuel Alito, who wrote the majority opinion. It also prompted some to question if laws like Ohio's could be challenged down the road as discriminatory. But more than anything else, it reflected a common theme that Sotomayor weaves into her opinions and speaking engagements: a law's effect on society.

Read More