In a 6-3 opinion, the state’s high court ruled that a supermajority law must be made through a constitutional amendment, rather than through legislation.
Ericksen says lawmakers need to pass an amendment to send to voters this November.
Democratic State senator Kevin Ranker says he does not support an amendment requiring a super-majority for taxes.
Voters have approved the supermajority rule in a number of initiatives sponsored by Tim Eyman, most recently in last November’s election.
The court’s decision is in response to a lawsuit filed by various groups against Initiative 10-53.
The ruling means the legislature needs only a simple majority in both houses and the governor's signature to pass a tax increase.