Or. Const. art. II, § 8

(1) The Legislative Assembly shall enact laws to support the privilege of free suffrage, prescribing the manner of regulating, and conducting elections, and prohibiting under adequate penalties, all undue influence therein, from power, bribery, tumult, and other improper conduct.

(2) The Legislative Assembly, the governing body of a city, county, municipality or district empowered by law or by this Constitution to enact legislation, or the people through the initiative process, may enact laws or ordinances within its jurisdiction that:

(a) Limit contributions made in connection with political campaigns or to influence the outcome of any election in a manner that does not prevent candidates and political committees from gathering the resources necessary for effective advocacy;

(b) Require the disclosure of contributions or expenditures made in connection with political campaigns or to influence the outcome of any election;

(c) Require that an advertisement made in connection with a political campaign or to influence the outcome of any election identify the persons or entities that paid for the advertisement; and

(d) Limit expenditures made in connection with political campaigns or to influence the outcome of any election to the extent permitted under the Constitution of the United States.

(3) Subsection (2) of this section applies to laws and ordinances enacted by the Legislative Assembly or the governing body of a city, county, municipality or district, or enacted or approved by the people through the initiative process, on or after January 1, 2016.