PORTLAND — Supporters of a failed referendum proposal to create a casino in southern Maine have dropped an appeal.

Secretary of State Matthew Dunlap announced earlier this month that campaign fell short of submitting the necessary 62,123 voter signatures to qualify for the November ballot. Casino supporters delivered 91,294 total signatures, but only 35,518 were deemed valid.

Casino supporters announced that they were appealing to the state supreme court. But supporters reversed course this week, withdrawing the appeal on Tuesday.

Casino supporters spent more than $2.9 million on the failed effort, making it one of the most expensive referendum efforts in state history. The campaign’s cash came from a single donor, Lisa Scott, sister of gambling entrepreneur Shawn Scott.