Hartig v. City of Seattle
They stated: "[I]t can scarcely be contended that this plan is inconsistent with a republican form of government, the central idea of which is a government by the people. Whether the expression of the will of the people is made directly by their own acts or through representatives chosen by them is not material. The important consideration is a full expression."
A similar (but federal) lawsuit in 1912 before the U.S. Supreme Court, Pacific States Telephone & Telegraph v. State of Oregon, determined that Oregon's I&R law was consistent with the federal constitution.