PORTLAND, Maine (AP) – Maine’s supreme court heard 11th-hour arguments aimed at stopping a GOP-led referendum on ranked choice voting and allowing the voting system to be used in the November presidential election.

Secretary of State Matthew Dunlap contends the GOP fell short of collecting 63,068 valid signatures for the November ballot. But the threshold was surpassed when a judge allowed 988 signatures from two people who didn’t register to vote until after they began collecting signatures. Dunlap contends signature-gatherers must be registered to vote before they start collecting signatures from voters.

Maine would become the first state in U.S. history use ranked choice voting for president if it’s able to use the method.